































































COPYRIGHT DEPOSIT. 







AUTOCRAFT 





AUTOCRAFT 


Being an Instructive Study of the Automobile; Its Care 
and Management; How to Drive; LocatingTroubles 
and Repairing Them; With Chapters Exploit¬ 
ing Some of the Latest Devices Used 
in Automobile Construction. 


BY 

Roy A. Engelman 


«v 

100 Illustrations 


1923 

American Automobile Digest 
Cincinnati 







TLfco8 
,E c 
ms 


V 


Copyright, 1924 

American Automobile Digest 
All rights reserved. 


n * > i 


©C1A766970 


FEB -4 ’24 

i 




INDEX 


A 

PAGE 

Automobile Engine—Its Operation and Construc¬ 
tion . 7 

Driving the Car. 30 

Care of Tires... 41 

Cleaning the Car. 70 

Symptoms of Common Troubles. 72 

What Is Horse-power?. 75 

Steering Gear. 84 

How to Oil an Automobile. 94 

Care of Axles. 98 

Motor Car Brakes. 105 

Carburetor . 113 

Magneto . 124 

Front Axle. 141 

Clutch . 149 

Electric Starters. 157 

Universal Joint. 166 

Motor Cooling System. 173 

Electric Wiring Plan and Coil Adjustment. 183 

Valve Grinding. 188 
























/ 



The Automobile Engine—Its Operation 
and Construction 

A UTOMOBILE engines are defined accord- 
ing to their cycle of operations. This term 
“cycle” is the successive actions of the 
piston, commencing when a certain relationship 
exists and starting again with the next recurrence 
of the same relationship. There are four events 
which must occur in an engine cylinder before 
it can repeat: 

First—Drawing in a fresh charge. 

Second—Compressing this so it can be ignited. 
Third—The explosion or expansion of the gas. 
Fourth—The discharge or exhausting of the 
spent gases. 

These events are termed the cycle of opera¬ 
tions, and these may be accomplished in two 
ways: first, by combining two of the events in 
one stroke of the piston; or second, by perform¬ 
ing each operation during one stroke of the 
piston. The former is termed the two-cycle or 
two-stroke type and provides a power stroke 
every revolution, while the latter provides a 
power stroke every other revolution and is 
termed the four-stroke or four-cycle type. 

The Four-Cycle Motor. 

The four-cycle motor is now almost univer¬ 
sally used for motor vehicles, and although the 
same operations must occur, they are controlled 
entirely by mechanical means. The cylinder 
ports are replaced by valves which Are either of 
the poppet, piston or sleeve type. The four¬ 
cycle type has been previously designated as a 

( 7 ) 


8 


Autocraft 


Ui 



* O 

cr s 

< mJ 
CL ft. 

CO 


Ui 

> 

-J 

< 

> 


to 

D 

< 

Z 

X 

UI 


to 

3 


Z 

X 

w 


Ui Ui 
*- > 

< -4 

- 5 

UI t_ 
-I 

(0 3 

< < 

s s 

2 UI 

UJ 

tr 


L- I- 
=3 3 
Z Z 

»- tt 

z u 
u o 


to 

“> 

o 


z 

< 

o 

h 

to 

o 

< 


X 

Ui 


o 

o 

cr 

O 


u 

Ui 

z 

z 

o 

U> 


* 

z 

< 

cr 

u 



SUCTION STROKE 







































































































Automobile Engine 


9 


UJ 


CL « 

> 


> 

-1 

Ul 

U -J 

< 

* 

-J < 

> 

< 

03 > 


»- 

< 

Ui 

z 

> “ 


•«• 

o * 

< 

K 

in 

* L 

z 

<’ 

Li z 


o 

a _ 


3 

Z 


Ul K 
Z 3 
K Z 

(/) 

3 * 
n U 
Q O 

< -J 


< 

U 

ui 

* 

< 


t 





cd 

4-* 

Q 


v 

X 


•o 

c 

03 

to 

to 

c 


S- 

5 * 

** 

.1 

J- X 

2 w 

*0 4 ) 

>>J; 

o< 

u 

3 

O 

pH 


to 

V 

o 

l-l 

H-* 

C/3 

o 

J3 


w. 

txo 

rt 


bi 

£ 





































































































10 


Autocraft 


four stroke engine, that is, one stroke of the 
piston is required to perform each operation. 
These four piston strokes are shown in Fig. 1. 
The intake, or suction stroke, is shown at “A” 
and it will be noted that as the piston travels 
downward the inlet valves open and permit the 
piston to draw in a fresh charge of gas from the 
carburetor. This valve remains open until the 
piston has passed the bottom of its stroke, and 
shortly after the piston starts on its upward 
completion of this piston stroke. During this 
upward stroke, which is shown at “B,” Fig. 1, 
the gases are compressed within the combustion 
chamber and prepared for ignition. The piston 
has now made two strokes and the crankshaft 
one complete revolution, while but two opera¬ 
tions have taken place. 

After completing the compression of the gases 
they are ignited by inducing an electrical spark to 
occur within the combustion chamber, which ig¬ 
nites the gases and raises their pressure four or 
five times what it was previously, causing them to 
expand and force the piston downward again, 
thus converting the heat of these gases into use¬ 
ful energy or power. This stroke, known as the 
power stroke, or working stroke, is shown at “C.” 
Now as the piston nears the bottom of this stroke 
the exhaust valve begins to open, as shown at 
“D,” and the spent gases begin to escape. This 
exhaustion of spent gases continues all through 
the following return stroke of the piston, the 
valve remaining open until the piston has again 
started downward a short distance. This com¬ 
pletes the four strokes and permits the motor to 
again resume its cycle of operations. 

In this illustration the valves are shown on 
opposite sides and although various valve posi¬ 
tions may be found in practice, this position sim¬ 
plifies the illustration considerable. 


Automomile Engine 


11 


Crankcase, Cylinders and Their Parts. 

In elementary form, the construction of a mo¬ 
tor car engine is quite simple, being comprised 
of a cylinder, a piston provided with rings 
operating within the cylinder, valves which 
permit proper timing for the entrance and dis¬ 
charge of the gases, a connecting rod for con¬ 
necting the piston with a crankshaft, a case or 
housing which supports this shaft and also a cam 
shaft which opens and closes the valves through 
cams mounted on the latter and a set of push 
rods. 

From what has been mentioned above in ex¬ 
plaining the cycle of operations, it can readily 



Fig. 2.—Sectional View of an “L” Head Cylinder. 


be understood that the piston travels up and 
down, forming a reciprocating motion, while 
the crankshaft rotates in its bearings in order 
to impart a turning effort to the driving wheels. 
This conversion of reciprocating motion into 
rotary motion will be described later. 

The Cylinder. 

The cylinders are usually gray iron castings, 
provided with water jackets or cooling fins, and 
have an open and a closed end, as shown in Fig. 
2. The inner walls are made very smooth by 
grinding, lapping or reaming so that the piston 






12 


Autocraft 


with its rings can slide freely within the cylin¬ 
der. The closed end forms the combustion 
chamber and houses the valves, which are in¬ 
serted through small openings in the head. The 
crankcase is the main housing for all parts and 
has the cylinders bolted to it. Cylinder con¬ 
struction varies according to the location of the 
valves and they may be cast single, in pairs or 
in blocs of three, four or six. 

The Piston and Rings. 

The piston of a gasoline engine is of the trunk 
type, being a trifle longer than the diameter of 
the cylinder. At a point approximately its cen¬ 
ter, bosses are formed on the inner walls on 
opposite sides which receive the piston pin, 
which acts as a hinge for the upper end of the 
connecting rod. Above and below this piston 
pin, grooves are formed which receive the pis¬ 
ton rings. These pistons are made a trifle smaller 
in diameter than the cylinder, to permit metal 
expansion, while the rings permit of flexibility 
so that the gases cannot escape by the rings. 

The Crankshaft. 

This is a horizontal steel shaft carried in bear¬ 
ings, inside of the crankcase, and it is provided 
with a number of offsets corresponding to the • 
number of cylinders. These offsets are termed 
the crankpins and carry the large ends of the 
connecting rods. The shaft also carries the fly¬ 
wheel. 

The Connecting Rod. 

The connecting rod forms an intermediate link 
between the piston and the crankshaft and its 
function is to transmit reciprocating motion into 
rotary motion. This conversion of motion may 


Automobile Engine 


13 


be described as follows: When the piston is at 
its top center in the cylinder the crankpin is 
standing vertical, however, as the expanding 
gases force the piston downward, the crankshaft 
is constrained and revolves downwardly. The 
crankpin which carries one end of the connect¬ 
ing rod passes through its horizontal position and 
finally reaches a position vertically below the 
center of the shaft. This same action of the 
crankshaft takes place as the piston moves up¬ 
ward, until the crankpin has made one complete 
revolution. Thus the upper end of the connect¬ 
ing rod reciprocates in harmony with the piston, 
while its lower end rotates in harmony with the 
crankpin. Fig. 3 illustrates a four-cylinder en¬ 
gine crankshaft with the connecting rods and 
pistons assembled to it. 

The Flywheel. 

The flywheel is used for storing energy devel¬ 
oped during the power stroke, which liberates it¬ 
self during the idle stroke. This function will 
be explained later under the caption of multi¬ 
cylinder engines. 

The Valves. 

The valves permit the entrance and escape 
of the gases at the proper time. These valves 
are usually of the poppet type and consist of 
a disc of metal with a stem on one end, which 
encloses a circular opening in the combustion 
chamber, being held against its seat by a coiled 
spring. 

The Camshaft. 

The opening and closing of these valves is 
controlled by the camshaft, which carries a 
cam for each valve. The camshaft is driven 
by gears from the crankshaft and in proper 


14 


Autocrajt 



I 

to 

bi 

U- 


Cylinder Crankshaft, Connecting Rods, Piston* and Rings. 










15 


Automobile Engine 

time relation with it. The cam causes the valve 
to raise from its seat while the spring performs 
the function of closing it. 

In this case it is necessary to convert a rotat¬ 
ing motion into a reciprocating motion, as the 
camshaft revolves while the valves have a recip¬ 
rocating motion. However, as no permanent 
connection is necessary, this becomes quite sim- 



Fig. 4.—Assembled Camshaft, Showing Cams, Bearings and 
Helical Tooth-Driving Gear. 


pie, by providing a push rod, one end of which 
communicates with the valve stem while the 
other rests on the cam. This push rod is pro¬ 
vided with a suitable bearing so that its relation 
with the camshaft can always be maintained. 
These push rods are always provided with an ad¬ 
justment so that as little lost motion as is practi¬ 
cal may exist between the valve stem and the 
cam. Fig. 4 illustrates a typical four-cylinder 
camshaft. 

The Crankcase. 

This forms the main structural part of the 
motor, carrying the cylinders, crankshaft, cam¬ 
shaft and accessories, and in turn is supported 
in the vehicle frame. It protects these important 
parts from mud and dust and also performs im¬ 
portant functions in connection with the lubrica¬ 
tion of the motor. The general construction de- 











16 


Autocrajt 


pends entirely upon the design of the engine, as 
regards cylinders, valve location, bearing mount¬ 
ing, etc. There are two general types, the divided 
type and the barrel type, the latter being 
shown in Fig. 5, together with the oil reservoir. 

Classification of Motors. 

Motor car engines are classified according to 
the type of valve employed and its location in the 
cylinder, as this point generally controls entire 
construction, as well as the various factors 
which enter into its design. 

These various types classified by the valve 
locations and type are as follows: 



Fig. 5.—Six Cylinder Barrel Type Crankcase and Oil Reservoir. 


Poppet Valve Type. 

“T” head—A type in which all valves are lo¬ 
cated in pockets on opposite sides of the cylin¬ 
ders. 

“L” head—A type in which all valves are lo¬ 
cated side by side in one pocket, or either the 
right or left hand side of the cylinder. 

“Valve in head”—A type in which all valves 









Automobile Engine 


17 


are located in the cylinder head, placed verti¬ 
cally or at an angle. 

There are also several other types which are 
combinations of those depicted above, having one 
valve in the head and the other in a pocket at 
the side, or both valves in a pocket at the side, 
one valve being located above the other. 

At present the “Valve in head” and “L” head 
motors are by far the most popular, although the 
other types are also used. In order to cover the 
general practice of engine construction, the 
writer is presenting a series of illustrations which 
cover all types of engines, together with descrip¬ 
tions, which will serve to point out the features 
of each construction. 

Motor Construction. 

Fig. 6 depicts the “L” head engine which is 
used on a number of popular-priced cars, and 
serves as an excellent illustration of the con¬ 
ventional type of “L” motor. The cylinders 
are cast in one bloc, integral with the upper half 
of the crankcase. The valves are located on 
the right hand side and the cylinder head is made 
detachable. The connecting rods are drop 
forging of I-beam section and are provided to 
facilitate bearing adjustment. The crankshaft 
is also a drop forging, however, it is mounted 
upon two bearings, one at the front and one at 
the rear, while lubrication is by the recirculating 
splash type, and cooling is by the thermo-syphon 
system. 

Fig. 7 illustrates the six-cylinder “L” head 
engine with en bloc cylinders and crankcase. 
The cylinders are also provided with a de¬ 
tachable head, but the crankcase is of a modi¬ 
fied barrel type with a pressed steel oil pan 
on lower half. The crankshaft is of the three- 
bearing type, while the camshaft is driven by a 


18 


Autocraft 




SO 

to 

• H 


Four Cylinder Bloc Motor “L” Head Type with all Valves on the right hand side. 

































































































































































Automobile Engine 


19 


silent chain instead of helical gears. Both these 
illustrations show how the valve stems may be 
enclosed and the direct valve operation through 
push rods of the mushroom type in Fig. 6 and the 
roller type in Fig. 7. 

Fig. 8 illustrates the “T” head motor, in 
which the valves are located in pockets on the 
opposite sides and are operated through push 
rods and a camshaft on each side of the engine. 
It is of conventional design. 

There are two types of valves in the head en¬ 
gines which differ chiefly in the location of the 
camshaft. This may either be mounted in the 
crankcase or on top of the cylinders. 

Fig. 9 illustrates the six-cylinder valve in the 
head engine in which the valves are located in 
the cylinder heads and are operated through 
push rods and rocker arms from a single cam¬ 
shaft located in the crankcase. Both the crank 
and camshaft are provided with bearings so lo¬ 
cated that each pair of crank pins are supported 
between bearings. 

When the camshaft is located on the cylinders, 
the valves are operated direct from the cams, 
and the valve stems are threaded to receive an 
adjusting nut. In this position the camshaft 
can either be driven through gears or a silent 
chain. 

Another type of motor still exists in which one 
valve is operated direct and the other through a 
push rod and rocker arm. This is known as a 
combination of the valve in head and “L” types. 
The Reo four-cylinder engine, Fig. 10, offers an 
excellent example of this type and one in which 
the cylinders are cast in pairs and bolted to a 
barrel-type crankcase. But one shaft is used, 
which is provided with three bearings, while the 
crankshaft also has three bearings. 


20 


Autocraft 



c 8gSS 




• ^ 
to 


Cross Section and Part Longitudinal View of the Six Cylinder “L” Head Bloc Motor. 




































































































































































Automobile Engine 


21 


There are various methods of driving the mag¬ 
neto and the water pump, and are dependent upon 
the general scheme of design. 



Fig. 8.—Cross Section View of the Mercer T Head Engine with 

valves on opposite sides. 


V-Type Engines. 

The trend of engine design has been toward 
increasing the number of cylinders and the writer 












































































































22 


Autocraft 


knows of but few exceptions when makers have 
decreased the number of cylinders. 

The present eight and twelve cylinder engines 
which are gaining favor rapidly, are built in what 
is termed V form. All cylinders could be ar¬ 
ranged in a row, but this would present some 
disadavantages, while the V type engine presents 
a very moderate length and in each case requires 
a somewhat shorter hood than a vertical engine 
of equal power, giving a somewhat roomier body 
with the same wheel base. 

Makers of these engines claim they exceed the 
six cylinder engine in flexibility, uniformity of 
torque and freedom from vibration. They are 
very smooth in operation as there is very little 
lapse, during impulses, eliminating the laboring 
jerks and jars. 

The development of the V type engine has been 
so rapid that design practice is rather chaotic and 
there is no uniformity in general layouts. 

These motors are generally of the L head or 
valve in the head type, as these two valve loca¬ 
tions seem to form the simplest arrangement. 
Opinions also differ as to the best method of at¬ 
taching the connecting rods and one finds two 
methods in vogue. These are placed either side 
by side, or one is forked and the other operates 
on a bushing within the fork of the former. 
There are also two camshaft constructions, one 
having eight cams and the other sixteen, while 
the valves may either be operated direct or 
through rocker arms. With the side by side con¬ 
necting rod arrangement it is necessary to stagger 
the cylinder blocks to center them with the con¬ 
necting rods. 

V-Engine Construction. 

The eight-cylinder V engine, Fig. 12, in some 
respect follows accepted practice, with cylin- 


Automobile Engine 


23 



>cr.fv 


oi 

QD 

• H 

ft* 


Longitudinal Section View of the Valve in Head Six Cylinder Engine. 






























































































































































































































































































































24 Autocraft 



































































































































































































































































25 


Automobile Engine 

ders arranged in blocs of four, side by side, 
connecting rods and rocker operated valves 
from a single shaft having sixteen cams. The 
engine is cooled by a forced water circulating 
system, which is maintained by a double water 
pump driven by a cross shaft at the front end of 
the engine, which also provides for driving a 
magneto when necessary. This water pump has 

SPARK PtUO 



Fig. 11.—Cross Section View of a Stearns-Knight Engine. 


two discharge pipes, one leading to each bloc of 
cylinders. The return path is by outlets for each 
cylinder bloc, the outlets being located opposite 
each exhaust valve. 

Lubrication of this engine is by a pressure feed 
system to all journals, regulated by a safety valve, 









































































































26 


Autocrajt 


which discharges the excess pressure of oil to the 
timing gears at the front end. 

Fig. 14 is somewhat different from the type 
mentioned above. The cylinders and crank case 
are cast integral and the valves are located in the 
cylinder heads, and are operated direct from the 
camshaft which has a cam for each valve. The 



Fig. 12.—Sectional View of Eight Cylinder Engine. 


connecting rods are of the forked type permitting 
the cylinder bloc to be set directly opposite each 
other. Each bloc of cylinders has its own water 
pump to maintain circulation, while lubrication is 
also by a pressure feed system. 

The Knight Motor. 

For some time the poppet valve motor, de¬ 
scribed above, was the only one which was com- 





































Automobile Engine 27 

mercially successful. However, in 1908, Charles 
Y. Knight introduced a sleeve valve motor, man¬ 
ufacturing rights of which have been granted a 







































































































28 


Autocraft 


number of American and European motor car 
builders. In this Knight engine the valve func¬ 
tions are performed by two sleeves, one within 
the other, and both between the piston and 
cylinder wall. Fig. 11 illustrates this type. The 
cylinder head is of unusual construction and 



Fig. 14.—Cross Sectional View. 


is made detachable. A part of this head ex¬ 
tends into the cylinder bore for quite a distance, 
but is of a smaller diameter, so that the sleeves 
may work between it and the cylinder walls. 

These sleeves, which replace the valves, are 
reciprocated by an eccentric shaft. This shaft 
has one eccentric for each sleeve which con¬ 
nects through short connecting rods with lugs 
formed on the sleeves at their lower ends. These 


















Automobile Engine 29 

connecting rods are of two different lengths, as 
shown. 

The movement of these two sleeves, which 
permit the gases to enter and escape, may be de¬ 
scribed as follows: Referring to Fig. 13, repre¬ 
senting the timing of the Stearns-Knight engine. 
Position No. 1 shows the inlet starting to open, 
while position No. 2 shows the inlet open, in 
this case the outer sleeve has moved downward 
and the inner sleeve upward until the ports in 
both coincide. Position 3 shows the inlet clos¬ 
ing, and 4 the top of the compression stroke. 
Position 5 shows the end of the power stroke and 
the exhaust begins to open, here the sleeves 
again bring the ports together, but in this case 
on the opposite side of the cylinder. By studying 
this illustration, the operation of a Knight engine 
can readily be understood. 


Driving the Car 

W ITH the number of automobiles rapidly 
increasing the highways become crowded ; 
therefore, in order to enjoy one’s auto¬ 
mobile, it is required of every driver to exercise 
a certain amount of caution. 

We as automobilists have rights on the public 
road. These same rights envelop responsibilities 
to many users of the highway. 

Some automobilists abuse their rights and heed¬ 
lessly run over the rights of others. A wrong 
and a right will not make a right. Therefore 
some suffer for the wrongs of others. Each acci¬ 
dent and wrong-doing on the highways has a 
tendency to arouse public sentiment against the 
motorist. 

The responsible operators must take it upon 
themselves to control the irresponsible operators 
and show them that they must operate their cars 
without menace *to life and limb upon the public 
highway. 

Many drivers, usually through thoughtlessness, 
do not practice the consideration for others they 
should have. Many lives are in constant danger 
and accidents occur with the driver who takes a 
chance. 

There is the driver who delights in exhibiting 
nerve stunts, such as remaining in the center of 
the road until almost upon the approaching ve¬ 
hicle, or the driver who will skid a car around 
instead of turning it as it should be done. 

Many such foolish pranks have resulted into 
serious accidents, also causing the loss of life and 
limb. 


( 30 ) 


Driving the Car 


31 


Law 


Traffic regulations have been adopted in all 
cities, and while touring through strange sec¬ 
tions it is well to become acquainted with them. 
We all know that it is unlawful to be without 
lights after dark. Nearly all the states require 
lamps to be burned on both front and rear of 
the car from sundown to sunup. 

Roads Intersecting, and Turning into 
Another Road. 

It is wrong to drive a car across an intersect¬ 
ing road or highway unless your view is entirely 
unobstructed. Many automobilists will drive 
over a thoroughfare unaware of what may be 
approaching on the road which crosses it at right 
angles. The blame for an accident in this event 
is on the cautionless operator. 

Turning into another road to the right, the 
operator should keep his car as close to the right- 
hand curb as possible. (Illustrated in Fig. 15.) 

Turning into another road to the left, the oper¬ 
ator should turn around the center of the inter¬ 
section of the two roads (as in Fig. 16). Fig. 17 
shows the wrong way to make a left-hand turn. 



Fig. 15. 


The operator of any vehicle who intends to 
turn or stop should always give the proper signal. 

In passing over railroad tracks it is advisable 
to drop back into second speed, in which instance 






32 


Autocraft 


you will avoid the possibility of stalling your 
motor on the track. Should you be compelled 


J L 



Fig. 16. 


J l 



Fig. 17 


to unexpectedly drive ahead fast with your car 
in second speed your chances of escape are easier 
and more certain. 

If you meet up with a frightened horse on the 
highway, drive your car to one side of the road 
and stop. 

The Changing of Gears. 


Before moving the gear shifting lever from one 
position to another the clutch sho,uld be- entirely 
disengaged. Unwillingness and laziness to change 
gears are the cause of many accidents and often 
very destructive to the car. 

At the proper time, instead of a driver chang¬ 
ing back into second speed, many allow the car 
to drift along until caught into a tight place in the 
traffic, resulting often in an accident. Use the 
second speed as often as necessary; it was installed 
in automobiles for good purposes; make use of it. 
We should never be in such a hurry that we can¬ 
not spare a few seconds for safety. You often 
hear the remark, “He lost control of the car.” 
Indeed, the driver in most all cases loses control 
of himself and not of the car. One is not an 










Driving the Car 


33 


expert driver until he intuitively performs the 
operations which control the car, just as one 
walks or reaches out for an object. 

Skidding. 

Skidding, a most dangerous element of motor¬ 
ing, is a helpless situation. It remains for the 
driver not to become confused to apply the brakes. 

Skillful handling of the steering wheel might 
in some instances prevent an accident from skid¬ 
ding. Reduce the speed of the motor, turn the 
front wheels in the same direction that the car 
is skidding, and don’t apply the brakes. 

If the front wheels skid, turn them in the oppo¬ 
site direction from which they are skidding. 

Crossing Street Car Tracks and Climbing 

Out of Ruts. 

Skidding can be prevented, accidents can be 
avoided, and the life of your tires lengthened if 
you will learn how to turn your car out of street 
car tracks or ruts. Make a sharp turn of your 
front wheels. Do not allow the wheels to climb 
along the edge of a rut and finally jump off sud¬ 
denly. And do not attempt to climb out of these 
conditions at speed. Haste surely makes waste 
in driving an automobile. 

Watch Your Car Closely. 

You will soon become accustomed to all the 
sounds your car makes. Any other sound, be it 
ever so slight, will be immediately perceptible. A 
good driver will immediately locate the cause.for 
that new and strange noise. It is the warning 
signal that something is not normal. It may be a 
loose nut. It may be a cry for grease. Do not 
disregard these signals. Locate the cause and 
give them immediate attention. Thus you will 
lengthen the service of your car. 


34 


Autocraft 


Driving Over Rough Roads. 

Keep the motor pulling your car slowly over 
rough roads. Thus it keeps everything taut and 
lessens the shock and jar that the car gets through 
bumping over ruts. 

Coasting Down Hill. 

In coasting down hill use the motor as the 
brake. That is, close your throttle and let the 
car drive the motor. This, of course, will not 
be sufficient to hold the car on very long and 
steep grades. It will serve, however, to relieve 
the strain on the brakes, and it will enable you 
to keep the car under absolute control. 

If the grade is long and steep, use the foot and 
emergency brakes alternately. This will prevent 
them from burning out. 7 

A Car's Service Depends Upon the Driver. 

Much of the satisfaction that an automobile 
gives depends upon the driver. If he neglects 
his automobile, if he does not lubricate it, or if 
he tinkers with it too much, he is bound to re¬ 
ceive unsatisfactory service. 

No machine can be absolutely automatic. All 
things must wear in time. The best preventive of 
wear, and the most certain thing for increasing 
the life of an automobile, is proper lubrication. 

Familiarize yourself thoroughly with all the 
lubricating points of your car. Make the lubrica¬ 
tion of your car as regular as is the eating of your 
meals. If you do this, you won’t have any com¬ 
plaint to make of your car becoming noisy or of 
bearings wearing out. If you don’t do it, you will 
not get the satisfaction from your car that you 
had expected. 

Operate Your Spark Lever. 

The spark lever is to be retarded whenever the 


35 


Driving the Car 

motor labors or pounds. In driving over rough 
roads, through sand and mud, or up hill, or when¬ 
ever there is a heavy load and the motor does 
not seem to run smoothly, retard your spark. 


Driving Pointers 

Don't Overlook the Spark. 

Many drivers entirely ignore the spark. As a 
result their motors do not give perfect service, 
and some cause considerable trouble. 

Coasting Mountain Roads. 

Whenever you approach a long and steep grade, 
it is best to put your gear speed lever into first 
speed and allow the car to drift down on the 
motor. This is better than using the brakes. It 
gives you absolute control of the car at all times. 

Coasting With Clutch Out. 

There is a satisfying sensation in allowing the 
car to coast along with the clutch disengaged. 
But do not under this condition, if the car is 
speeding, let the clutch in when the motor is run¬ 
ning slowly. It produces too severe a shock on 
the entire driving mechanism. Speed your motor 
up to as great or a greater speed than the car is 
traveling, so that the shock will not be so severe. 

In all cars such a plan of driving results in 
strains, often so serious that the transmission is 
wrenched from its anchorage. The clutch is 
damaged, and accidents have resulted. 

Know Your Car. 

Your satisfaction will be greatly increased if 
you will learn the details of your automobile. 
Learn to make the simple adjustments. Do not 
depend upon some one else to do that which is 
so simply done, and which you can get such satis¬ 
faction in doing. 



36 


Auto craft 


The Cost of Speed. 

The law is just as immutable in that it collects 
a greater cost for speed in a motor car as it does 
of any machine or of man. If you run fast, if 
you work hard, you require more food to sustain 
you. If you drive your car at a fast speed all 
the time, it requires more fuel—more gasoline 
and more oil. 

If you work fast and hard, you wear out more 
quickly, and so does an automobile. 

Tires, for instance, last twice as long on a car 
that is driven at fifteen miles an hour as they 
do upon cars that are driven at thirty miles an 
hour. 

Remember that the service your car gives you 
is as much dependent upon the manner in which 
you operate it as is your own health dependent 
upon the manner in which you care for it. 

Through Sand and Clay. 

Heavy sand: Deflate tires, but not to a degree 
dangerous to the rim. Use chains. Pump up 
tires immediately after passing through sandy 
stretch. 

Soft clay, etc.: Do not deflate tires. Use loose 
chains. In very bad places at times when no 
friction is gained, do not spin the driving wheels 
as this only enlarges the hole and increases the 
trouble. Jack up car first, then fill in the rut or 
hole that has been made. Most trouble occurs 
on the off-side of the road. Keep to center as 
much as possible. 

Do Not Drive in Ruts. 

Driving in ruts is not only bad for the tire, but 
it is equally bad for the highway. It is only 
the lazy driver that “sticks” in the ruts rather 
than being awake and on his guard to avoid them 

Continued driving in one line or spot quickly 
eats through the top dressing of the macadam 


Driving the Car 


37 


road and wears the hole or rut in the body of 
the best road. This is the difficult damage to 
patch, without renovating almost the entire road¬ 
way, and motorists should be glad to co-operate 
to this extent in keeping good the better highway. 
Do not drive in ruts. 

Don’ts. 

Don’t strain your motor through laziness of 
shifting into a lower gear. Serious results occur 
from forcing the motor on steep grades and 
heavy pulls in the high gear. 

Don’t drive in car tracks, especially on wet 
pavements. Many accidents occur to motorists 
who haven’t been able to get their car from the 
rails when suddenly and unexpectedly required 
to do so. 

Don’t take chances of looking through the 
wind-shield or celluloid curtains while same are 
covered either with rain or snow. Always stop 
and clean off. 

Don’t forget that sometimes the pedestrian 
who would walk in front of your path may be 
some unfortunate blind or deaf person. 

Don’t be inconsiderate to the pedestrian on 
the walk by splashing him full of mud. It is 
easy enough to slow down or drive to one side of 
the road a trifle, thereby omitting this offense. 

Don’t test your automobile in the busy thor¬ 
oughfares. After you have finished your work, 
drive out to some roadway where you will be 
free from pedestrians, traffic, etc. Many drivers 
and repairmen who work for garages centrally 
located often meet with accidents because after . 
having made a quick and hurried repair they 
drive out in the down-town district, crowded 
with people and traffic, to determine the results 
of their work or test out the car. 

Don’t drive on in case of an accident. 


38 Autocrajt 

Don’t fail to be a gentleman under any provo¬ 
cation. 

Don’t exhibit grandstand acts by driving upon 
a crowd of people and suddenly opening the ex¬ 
haust cut-out, at the same time racing the motor, 
or by skidding around instead of going back and 
forth until you have made a complete turn. Re¬ 
member that while the automobile is flexible, pow¬ 
erful and easily controlled, you may make a slip. 

Don’t drink if you intend operating an auto¬ 
mobile. Many accidents occur to automobiles 
driven by intoxicated operators. 

Don’t ever get rattled. 

Don’t try to race every car which passes you. 

Don’t drive your car on car tracks; it is an 
expensive luxury. 

Don’t drive fast around corners, as this will 
cause side strain and a grinding wear on the 
tread of tires. 

Don’t pass a street car while it is at a standstill. 
Passengers often alight without looking for any 
approaching traffic. Stop still until the street car 
is again in motion. 

Don’t try and dodge an excited pedestrian in 
the street. He or she will go back and forth 
much confused and finally run directly in front 
of your machine. Stop as quickly as possible, be¬ 
cause in many instances it has proven to be either 
an intoxicated person or the one who thinks “Hit 
me and I’ll sue you!” 

Don’t stop to argue with drivers of teams, 
trolley car motormen, etc. It often occurs that 
the other fellow is ignorant of your rights, and 
persistence on your part may some time result 
in an accident. 

Don’t forget that vehicles do not have the right 
of way at street crossings. 

Don’t curse police officers. We should all co¬ 
operate with the police force to assist in reducing 


Driving the Car 


39 


the number of accidents caused by reckless driv¬ 
ing. Careless pedestrians, particularly those in 
congested districts, lack attention in crossing 
streets. It is your duty as a citizen to understand 
the rules and regulations of “street traffic/’ and 
especially those rules concerning the community 
of which you are a resident. A definite knowledge 
will aid materially in causing traffic conditions to 
steadily improve. 

Don’t pass another car with the intention of 
lingering after you have passed, whereby they 
receive, in return for their kindness in allowing 
you the right of way, your dust. Either pass 
them, maintaining your passing speed, or continue 
to drive far enough ahead until you have reached 
such a distance that burnt oils and gases dis¬ 
charged from your car, together with the germ- 
filled dust, won’t interfere with the following car. 

Don’t travel over unknown roads at a break¬ 
neck speed, for a little “thank-you-marm” might 
set you in the flowers. 

Don’t be a road hog because you have a smaller 
car or because you don’t care to drive any faster 
than the speed you are traveling at the time. If 
another car is desirous of passing you, keep to 
the extreme right of the road until same has 
passed; then, if your roadway is again clear, re¬ 
turn to your former position on the road, driving 
along at the speed which you care to maintain. 

Don’t neglect to test batteries. 

Don’t leave your car with motor running. 

Don’t stop your car on the wrong side of the 
street. 

Don’t fail to always release hand-brake before 
attempting to start. 

Don’t start out on a trip without attention to 
oil, gasoline and water. 

Don’t throttle your car in jumps, as this is very 
injurious to working parts. 


40 


Autocrajt 


Don't ever drive faster than the law permits; 
it will save you many a fine. 

Don’t fail to keep brakes properly adjusted; it 
is more important to stop a car than start it. 

Don’t use the electric starter continuously to 
demonstrate its operation unless you in turn run 
the motor sufficiently to recharge the storage bat¬ 
tery. 

Don’t forget to see that your gasoline tank is 
full before starting out on a long trip. It is much 
more convenient to fill the tank at a garage than 
when on the road. 

Don’t put acid in the jars of the storage battery 
to raise the specific gravity, unless the electrolyte 
has been spilled out, and it becomes necessary to 
mix up a new solution. 

Don’t forget the automobile is one of the finest 
pieces of machinery manufactured, and you will 
be repaid in excellence of service many times for 
the proper care and attention you give it. 

Don’t run on the dry battery unless the mag¬ 
neto circuit is somehow impaired. It is much 
easier to start on the dry battery circuit, and it 
should be kept in order for this purpose. 

Don’t fail to put a small quantity of distilled 
water in the storage battery occasionally. Water 
will evaporate, but acid will not. If the solution 
evaporates so that the wood separators are ex¬ 
posed to the air, they will be completely burned 
up by the acid and new T ones will have to be in¬ 
stalled. 

In laying up your car for two month’s or more, 
jack it up clear of the floor, allowing the axles to 
rest on supports. Allow all air to escape from 
tires except enough to shape them. 

Because rust eats into the fabric, rims should 
be sandpapered and painted preferably with 
graphite. Paint or any other rust preventive 
will do. 


The Care of Tires 

The “Reason Why"' of the Pneumatic Tire. 

T HE pneumatic rubber tire is especially 
adapted to the automobile, because of its 
resiliency (something akin to the “bounc¬ 
ing” properties of a rubber ball) which enables it 
to absorb the shocks caused by the unevenness 
of the road surface. 

This combination of air and rubber—the two 
most elastic substances in existence, is ideal for 
the purpose, forming an efficient cushion, yet suf¬ 
ficiently strong and wear-resisting to carry the 
heavy weight of the car and its occupants over 
the worst kind of roads. 

But rubber alone is not enough; it needs air 
and plenty of it. Air is so cheap, there is no 
excuse for rim-cutting or other similar troubles 
which are caused by under-inflation. 

Principles of Tire Construction. 

An automobile tire is something more than a 
mere tube of rubber with air inside it. 

To build a tire with the requisite combination 
of strength and resiliency requires a combination 
of skill and experience such as is demanded of 
few other items of automobile equipment. 

A strong tire alone would be easy. Steel is 
strong. A tire would be resilient if simply made 
of rubber alone, but would not wear. Hence the 
combination of rubber and fabric with which we 
are all more or less familiar. 

To hold the tire on the rim, some kind of “grip” 
is required so that a complete tire casing consists 
essentially of a rubber outside, a fabric “carcass” 
and beads or grips to hold it in place. 

(41) 


42 


Autocrajt 


The fabric is in itself the subject of special 
study. 

Not every kind of fabric is suitable for tire 
purposes, and after many years of experience with 
materials of all descriptions, the only one found 
to possess the requisite qualities has been sea 
island cotton, of which, however, only the very 
finest long staple grades can be used. 

At every stage of its manufacture, the material 
is carefully examined and the least defect is suf¬ 
ficient to cause its rejection. When received at 
the factory it receives a final rigid inspection and 
is then ready for the friction calendars. Here it 
passes through heavy steel rolls and is thoroughly 
impregnated with rubber. 

Next, it is carefully cut into strips on the “bias” 
of the material, this being necessary for the 
proper distribution of the stresses evolved in run¬ 
ning over the entire body of the tire. 

This having been done, it is ready to build up 
into the tire itself. 

Types of Tires. 

The various plies of fabric having been pre¬ 
viously frictioned and cut into strips, are carefully 
laid one upon another, on a form, care being 
taken that each layer “breaks joint” with the one 
below. 

The first plies are slightly wider than the suc¬ 
ceeding ones, for a reason which will be presently 
seen. 

The requisite number of plies having been laid, 
the next processes are the applying of the side 
walls and beads. These beads are made of a 
harder compound and, having been laid in place, 
the first plies of fabric are carefully tucked in 
around so that the beads are firmly held in place. 

Each succeeding layer is firmly rolled down 
onto its predecessor. Next a thick “cushion” layer 


43 


Care of Tires 

of rubber is applied, then the “breaker strip,” 
and lastly the tread is applied. This is much 
thicker than the side walls and is a specially tough 
compound suitable for withstanding the heavy 
wear and tear of the road. The function of the 
breaker strip is, firstly, to reinforce the tread, 
and, secondly, to act as a warning signal that the 
tread is getting worn out and the tire needs re¬ 
newal or retreading. 

In its essentials, then, a tire resembles a shoe, 
the fabric standing for the lining, the side walls 
for the uppers, while the sole of the shoe is re¬ 
placed by the tread. Just as these three parts are 
of varying strength in the shoe, so they are in the 
tire, each carefully proportioned to the work it 
has to do. 

Conforming in general construction to the reg¬ 
ular lines already mentioned, it differs from other 
types mainly in the fact that the beads are made 
of rubber alone, and while firm enough to hold 
rigidly in place, are yet sufficiently flexible to 
allow removal from the ordinary one-piece (or 
clincher) rim. 

The only point of difference between this tire 
and the quick detachable type is the bead con¬ 
struction. 

In the quick detachable tire the bead is stiff and 
inextensible, the removal of the tire being effected 
by removing side, a rim which is made detachable 
and held in place with nuts and bolts. 

The ring being removed, the tire easily slides 
off, and is just as readily replaced. 

The straight bead type of tire has some fol- 
lowers, but little different in construction from 
the ordinary clincher type, the change again being 
in the bead. In this tire the projecting bead of 
the clincher is absent, being replaced by a special 
form which depends for its grip on the pressure 


44 Autocrajt 

of numerous strands of fine wire embedded in the 
rubber. 

Being used in a straight-side rim, the air space 
is slightly larger, while the rounded edges of the 
rim obviate any tendency to rim-cut when the tire 
is run “flat” (that is, empty), a practice, by the 
way, which cannot be too strongly condemned. 



Fig. 18. 

This tire cannot be used on a clincher rim, 
but may be used on an ordinary quick-detachable 
rim by simply reversing the flanges. 

Cord Tires. 

Two layers of these cords are applied one over 
the other in the following order: 

First a layer of pure rubber is applied to the 
form. Next a series of staples, 300 in all, are set 
at short stated intervals around the inner edge 
of the bead and on these the first layer of cords 
is laid by a machine, which places each cord accu¬ 
rately in its appointed place, giving it at the same 
time the requisite amount of tension. 



Care of Tires 


45 


When the first layer is completed, a second 
layer of rubber follows, then another of cord. 
A third cushion layer of rubber follows, finishing 
with breaker strip, tread, side walls and beads as 
in the other tires. 



TREAD^ 

^ BREAKER STRIP^ 

1CUSHION LAYER- 

I — CORD LAYER- 

2— CUSHION- 

2— CORD- 

INNER GUM- 

SIDE WALL-— 

BEAD FABRIC- 

ANTI RIM CUT STRIP 
BEADv \ 


It is worth noting that in the process of manu¬ 
facturing the cords each is twisted up of 24 sepa¬ 
rate threads, the threads themselves being thor¬ 
oughly impregnated with pure rubber both before 
and after twisting. 


Fig. 19.—Goodrich Cord Tire. 

The great strength of this form of construction 
lies in the fact that each cord forms a separate 
unit, distributing the strain and blows of the road 
over the entire body of the tire, that it is more 
resilient because less rigid than a fabric tire and 
is more easily repaired. 

Although of lighter construction than a fabric 
tire, it is for these reasons really much stronger. 














46 


Autocraft 


The Inner Tube. 

The inner tube has not been inaptly termed th£ 
“heart” of the tire. It is necessarily made of the 
best procurable quality of rubber, since it must 
withstand the heavy pressure demanded while at 
the same time preserving its elasticity. 

In making a tube, the rubber is first rolled into 
sheet form, then wrapped layer after layer on a 
steel mandrel, each layer being carefully rolled 



Fig. 20. 


down on the preceding one until the requisite 
thickness is attained. 

After curing, the tube is cut to the requisite 
length, the ends buffed and spliced, and it is care¬ 
fully tested for possible defects before packing 
for shipment. 

The illustration shows a small section of an 
inner tube with valve in place. 

The Care of Tires. 

Some owners run the year round without a 
single trouble, getting more enjoyment out of an 
old runabout than another man from his high- 
powered, six-cylinder, all up-to-date-and-a-bit- 
over auto of the most expensive build. 










Care of Tires 47 

Maintenance is largely a matter of care and 
attention. 

If you don’t feed and groom a horse regularly, 
he soon gets out of condition, yet the car goes 
out into the rain, over the worst kind of roads. 

In the matter of tires alone, over 75 per cent 
of the user’s troubles arise from misuse. 

“Neglected trifles” is a fair summary of the 
whole question. 

Look over your tires today. Ten to one you 
will find at least one or two cracks or pinholes, 
apparently not amounting to anything at all. But! 
Clean one out carefully and follow it up. It ex¬ 
tends right down to the fabric, and every time 
that part of the tread touches ground the tire is 
one more stage on its way to the “graveyard.” 
Wet and sand find their way in until at last the 
tread blisters or peels ofif bodily. 

An ounce of prevention is worth a ton of cure, 
and frequent overhauling of your tires and the 
immediate repair of even the smallest cut will 
materially help to lengthen the life of the tire. 

Here is shown a tire that has blown out, due 
to neglected repairs. It originally had a small cut 
entirely through. An inside patch was applied by 
the owner, he feeling that this was all that was 
required to place the tire in good running order, 
but instead, the inside patch merely aggravated 
matters and, acting as a wedge, caused the tire 
more harm than good. The result, as shown in 
the picture, was that the tire blew out from bead 
to bead, that is, the inner patch wedged the fabric 
apart, causing it to break or pull apart from bead 
to bead. 

By looking closely you can see how the patch 
has pulled away from the position it originally 
held, and has been forced through the break, pro¬ 
truding on the outside. (Shown in Fig. 22.) 


48 


Autocraft 



Fig. 21.—Blisters Caused by Neglected Cuts, 








Care of Tires 49 

We class this a condition due to a neglected 
repair, as it does not follow from any weakness 
in the tire, but has resulted from the tire not re¬ 
ceiving the proper attention when it was first cut. 


Fig. 22.—Blowout from Neglected Repairs. 

Under-InflatioM. 

Under-inflation produces over-heating. This 
in turn saps the life of the fabric in the tire, 
destroys the cohesion between its various plies, 










50 


i 

Autocraft 



Fig. 23. — Result of Fig. 24. — Effect of 

Under-inflation. Running Out of 

Alignment. 










Care of Tires 


51 


and allows the tread to loosen up all round. If 
the injury were confined to the latter only, it could 
be repaired by retreading. The cost of this would 
be approximately one-third the original cost of 
the tire and the ultimate mileage would be re¬ 
duced. So the penalty of running under-inflated 
is costly. On the other hand, where the plies of 
fabric separate, repairs cannot be made at all, 
and the tire if cut through or broken by a stone- 
bruise is worth only junk value. 

Another point worth considering is the much 
talked of “rim-cutting.” No tire will rim-cut if 
it be properly inflated, but any tire will be irre¬ 
trievably damaged by being run ever so short a 
distance in a deflated or even partly deflated con¬ 
dition. 

Running Out of Alignment. 

This and many other tire troubles are clearly 
the fault of the driver and should never occur if 
the tires are properly cared fc*r and small repairs 
attended to at once. 

A corhmon source of tire trouble is premature 
wearing out of the treads, from the wheels being 
out of alignment. This is generally a condition 
of the front wheels, though it may affect the rear 
wheels. It can be easily located by measuring 
the distance between the two wheels with a stick, 
both ahead and behind the axle. The effect is to 
grind off the tread and ruin the tire. In aggra¬ 
vated cases, the damage may be complete in a 
hundred miles. The remedy is to have the align¬ 
ment corrected and the tire re-treaded, if it is 
otherwise in good condition. A very similar re¬ 
sult is produced by a wheel out of true or wobbly, 
the wear appearing at fixed intervals around the 
tire. 

Any cut which reaches the fabric ought to be 
repaired with a vulcanized patch. If small, it can 
be sealed with a plastic compound, which keeps 


52 


Autocrajt 


out moisture and dirt. It may not hold in the 
larger cuts, however, and these should be vul¬ 
canized. 

There are a number of handy portable vulvan- 



Fig. 25.—Tread Worn Off by Skidding. 

izers in the market which, if properly used, are 
all right for the average tread cut. Too large a 
repair should not be undertaken with them, as 
the necessary pressure for such cannot be secured. 






53 


Care of Tires 

Great care should be exercised lest you burn the 
tire, for the heat is difficult to control in these 
small vulcanizing devices. To some extent this 
tendency can be overcome by putting a sheet of 



Fig. 26.—Fabric Destroyed by Inner Liner. 


paper between gum and vulcanizer. They are, 
however, more adaptable to tube repairs, which 
with a little experimenting can be worked out 
very nicely. 





54 


Autocraft 



Judgment should be used in applying chains. 
These should always be adjusted loosely so that 
they strike the ground ahead of the tire. In this 
way the maximum non-skid effect is produced 


Fig. 27. Cut and Torn by Improper Use of Chains. 

and they do not bind and tear the tire as the> 
would do if adjusted without plenty of play. 
Avoid locking your wheels with the brakes. No 



Care of Tires 


55 


tire will withstand the strain of being dragged 
over a pavement in this fashion. The heat will 
burn it through in a few seconds if the speed and 
load be enough. Besides, the danger of accident 
from a skidding machine is increased. Let the 
brakes do the work of stopping the car, by proper 
application. Do not put this work on your tires. 

The strain caused by the sudden stopping of 
a 2,000 or 3,000 lb. car, running at 20 or 30 
miles an hour, is really tremendous, and no 
amount of human ingenuity can ever invent a 
material capable of withstanding such a shock. 
Steel itself would be disintegrated in time by such 
treatment. Heavy loads and excessive speed have 
the same tendency, the initial cause of which is 
the intense heat generated inside the structure of 
the tire itself, destroying the resiliency of the 
rubber and making it brittle and non-elastic. 

Do not use too much soapstone inside your 
cases. This will accumulate at one point, fric¬ 
tion will be set up, and the tube will soon be honey¬ 
combed with small blisters, presenting a bubbly 
appearance. 

Keep away from inner liners in new or service¬ 
able cases. They may extend the life of old and 
worn-out tires by an additional 500 miles or so, 
but they will ruin good tires through the fric¬ 
tional heat engendered. 

Stone bruises are not an infrequent trouble. 
Let us say at once, these are the motorist’s own 
fault. 

Any one who deliberately drives over a heavy 
stone or similar obstacle is literally asking for a 
blowout. 

The reason is that the effect of a heavy car at 
a high speed, striking a stone, is just the same as 
that of a heavy missile hitting the tire. Some¬ 
thing has to give way, and this is usually the 
fabric. 


56 


Autocrajt 


Sometimes this injury does not become known 
for a long time, but sooner or later a blowout is 
inevitable. 

Running in ruts or car tracks is another easy 
way of spoiling a tire. 



Fig. 28.—Fabric Broken by a Bruise. 


The tread is like a boot sole, made for hard 
wear, but the side walls may be compared to the 
boot uppers. The result of running in the man¬ 
ner indicated is to wear off the sides, which are 
speedily ruined, although the tread may be intact. 
This kind of injury is almost impossible to repair, 
so every care should be taken for its avoidance. 







Care of Tires 


57 



Fig. 29.—Effect of Running in Ruts or Car Tracks. 

Reckless or careless driving cannot be too 
severely condemned. Even if no accident occurs, 
it is utterly destructive of both tires and ma¬ 
chinery. 


The foregoing are some of the more common 
causes of tire trouble. All of them may be 
avoided by a little care and attention to common 
sense rules. 







58 Autocrajt 

How to Temporarily Repair an Inner Tube. 

Inner tube must be removed from casing to 
repair puncture. If puncture is invisible, immerse 
inflated tube in water. Air bubbles will locate 
trouble. 

For quick and handy roadside repair, use 
patches, as shown in accompanying illustration. 


When using patches, select the required size of 
patch. The surface around puncture in the tube 
should be roughened with coarse emery cloth or 
metal buffer. Cover the roughened surface of 
the tube around puncture with cement, applying 


Fig. 30. 







59 


Care of Tires 


three coats at intervals of about five minutes. 
Allow this surface to dry until the treated sur¬ 
face is quite sticky to the touch. This requires 
about twenty minutes from the time the first 
coat of cement is applied to the tube. Press 
patch down firmly. Spread some French chalk 
over the repair to prevent it sticking to the casing. 

Before replacing the tube allow a short time to 
elapse for perfect adhesion. 

Before replacing the punctured tube, examine 
the inside of the case carefully, and remove the 



cause of the injury (in most cases a tack or small 
nail). Often this can be located only by a minute 
examination or by passing the hand inside of tire. 

When using Quick-Detachable Clincher or 
Straight Side tires, see that the flap is properly 
adjusted before placing tube in casing. A pinched 
tube will cause a tube blow-out. 

Note.—Place the tube in the hands of a com¬ 
petent vulcanizer at the earliest possible moment 
for a permanent repair. 


A Temporary Repair to Casing. 

If the puncture has been caused by a thin nail, 
use an Emergency Tire Saver Patch, which is 
coated with rubber on one side. First clean the 
inside of the casing thoroughly with gasoline and 
roughen with emery cloth, then apply two or 
three coats of Dry Patching Cement, allowing 
each coat to dry until it is quite sticky to the touch. 




60 


Autocraft 


Then remove the wax paper from the emerg¬ 
ency Tire Saver Patch, moisten with gasoline, 
and apply to the inside of casing. 

Even when the hole has been made by a blunt 
obstacle, such as a thick screw, an Emergency 
Tire Saver Patch, applied as stated, will make an 
effective temporary repair. 

After the Emergency Tire Saver Patch has 
been applied, do not neglect to freely sprinkle both 
patch and space about it with Tire Talc. This 

is to prevent ad¬ 
hesion of the tube 
to the repair. 

In case of a 
large cut or blow¬ 
out, use an Inside 
Blow-out Patch 
and Hook-on-Boot 
or Lace-on-Boot, 
thereby preventing 
sand and water 
from working into 
the tire and caus¬ 
ing more serious injury to tube and casing. The 
flaps of the inside blow-out patch ar^ locked 
around the bead of the casing and require no 
cement. The Hook-on-Boot is placed over the 
casing while deflated and hooks in the rim. When 
Lace-on-Boot is used it is placed on the outside 
and laced around the tire, rim and felloe of the 
wheel. 

Tire Tape is an essential part of a repair outfit. 
Every motorist should carry a roll. 

Note.—Put the casing in the hands of a com¬ 
petent vulcanizer at the earliest opportunity. 

Punctures. 

There is no hard and fast rule for avoiding 



Care of Tires 


61 


punctures. But you can keep a puncture from 
ruining the whole tire. 

Don't run on a deflated tire. 

If you are unfortunate enough not to have de¬ 
mountable rims or even a spare casing or tube, 
stop short. Better take off the tire and run a 
short distance on bare rim, than continue on a 
deflated tire. 

Blow-Outs. 

Blow-outs can be traced to a number of causes. 

You may have bruised your tire last week, or 
last month, and even though the tread shows no 
sign of being injured, the inside fabric was broken 
and every revolution after that weakened the 
fabric, and a blow-out follows. 

Overloading puts too much extra strain on the 
tire—a blow-out may result. 

Under-inflation places a strain on the tire by 
bending the sidewalls and breaking the fabric. 
This never occurs if tire is properly inflated. 

Cuts. 

Watch for cuts in the thread. 

Don’t neglect the small, apparently unimportant 
ones. They will not remain unimportant. 

Water will enter through cuts and rot the fab¬ 
ric. Sand and grit will work in between the 
rubber and the fabric, and in a short time will 
loosen the tread. 

Examine the treads from time to time.. 

Large cuts, particularly where fabric is injured, 
should receive the immediate attention of the 
repair man. 

Bruises. 

Examine the inside of your casings from time 
to time for bruises. 

A sharp blow from road obstructions, car tracks 
or curbing will bruise a tire, and may fracture 


62 


Autocrajt 


the fabric inside the casing. You cannot locate 
a fracture of this kind on the outside of the tire. 

The casing with fractured fabric should receive 
the immediate attention of the repairman. 

Chafed Side Walls. 

Avoid driving in car tracks, against curbs or 
in deep ruts, as it chafes the rubber on the side- 
walls of a casing. 

In order to give flexibility the sidewall com¬ 
pound has a much higher proportion of pure rub¬ 
ber than the tread, and consequently will not stand 
as much abrasion. 

A badly worn sidewall permits water to enter 
and rot the fabric. 

I 

Don't Run on Deflated Tires. 

If you run a tire deflated, the grinding and 
crunching between rim and road will speedily 
ruin it. 

Examine Rims. 

Be sure your rims are clean and true. Dents 
or irregularities in your rims often cut or chafe 
the sidewalls of the tire. This permits the en¬ 
trance of moisture, and decay is sure to follow. 

A little attention to your rims may save many 
bills for tire repairs. 

Under-Inflation. 

Tires are made to carry certain loads and with¬ 
stand ordinary strains—but to do this the tire 
must be pumped up to the required pressure. 

When you use less than the proper amount of 
air the casing itself must bear more than it was 
built to carry. Result: the length of your tire 
service is materially reduced. 

Further, the constant bending of fabric when 
running tires soft, causes overheating and tears 


63 


Care of Tires 

the layers of fabric apart. A blow-out will follow. 

An air-pressure gauge will enable you to know 
when your tires are inflated to the proper degree. 
Don’t trust your eyes, but get a gauge. 

Overloading. 

The strain of extra weight will fracture the 
tire fabric in a short time. 

If you are accustomed to carrying more pas¬ 
sengers or heavier baggage than your tires are 
intended to stand, equip your car with over-size 
tires. 

More air capacity alone does not make an over¬ 
size tire; real over-size is obtained by thicker 
treads, and heavier sidezvalls—heavier construc¬ 
tion throughout the tire. 

Chains. 

Chains and other tire-destroying metal devices 
will materially lessen the life of a tire. 

They will cut through the tread, and often 
through the fabric. Water will enter the breaks 
and rot the carcass. Grit and dirt will soon work 
between rubber and tread, ruining the casing be¬ 
yond repair. 

Skidding and Improperly Adjusted Brakes. 

Brakes not properly adjusted are the cause of 
many casings wearing out prematurely. 

One brake is sometimes tighter than the other, 
placing most of the strain on one tire. 

This has the same effect on the casing as skid¬ 
ding. It soon grinds the rubber off the tread. 

Have your brakes adjusted if your tire shows 
the tread ground down in spots. 

The Changing of Tires. ♦ 

See that your jack is set firmly and is perpen¬ 
dicular. Do not place it against the truss rods, 


64 


Autocrajt 


but under the axle or under the spring bolts, 
where it cannot damage the machine. 

After removing dust cap, remove valve plunger 
to hasten the deflation of the tube. Don’t leave 
the dust cap, valve cap and plunger lying on the 
ground, but put them in your pocket or some 
place where they will be handy when you want 
them. Always have a few new valve plungers 
with you, as many a slow leak originates in a 
bad plunger. 

A Three-in-One tool is a most valuable acces¬ 
sory. While you can remove the valve plunger 
by inverting the valve cap, the tool is handier 
and also enables you to remedy battered threads 
both inside and outside the valve. After deflat¬ 
ing, turn the wheel until the valve is down, and 
push the valve stem into the case. Pull the tire 
toward you, so as to loosen the back bead, begin¬ 
ning at the top. The front bead will slip off 
readily enough, but the back one will sometimes 
stick. In that event reach into the case and pull 
the valve stem out. You will then have no trouble. 

On Proper Inflation. 

There is no one thing more important in the 
care of tires than to keep them inflated properly. 

A good rule is to allow the tires to show no de¬ 
pression under the weight of the car when stand- , 
ing on a level floor. A daily test of the air 
pressure is necessary if the bad results of under¬ 
inflation are to be avoided. 

Punctures. 

If a tire leaks it may not always be from a 
puncture. Test your valve first. This is easily 
done by moistening the valve cap washer before 
screwing down. If there is a leak small bubbles 
of air will be seen issuing from around the edges 
of the cap. 


Care of Tires 


65 


Pinched Tubes. 

Ninety per cent of tube troubles are due to 
pinching, from improper application of the tires 
to the rim. Either a flap gets misplaced, a tire 
tool gets jammed against the tube or the beads 
of the case catch it at some place where it is 
creased. Practically all instances of a tube let¬ 
ting go inside the case, without outside evidences 
of injury, are due to this cause, or to a bruise 
break in the fabric pinching the tube. 

When a tube is put in a case it should be lightly 
inflated and the hand slipped around inside the 
case to feel that there are no wrinkles. The flap, 
if any, should be put in position in the same way. 
After the case is on and before final inflation, the 
bead should be raised all around with a tire tool 
to allow the tube to escape into place if the beads 
are pinching it anywhere. 

Many tire experts agree that more than half 
of the number of tire troubles are due directly or 
indirectly to underinflation. As it is, in the case 
of the pneumatic tire, not the rubber but the air 
which carries, suspends and cushions the weight 
of the vehicle—everything, of course, depends on 
having as much air as possible in the tire tube, 
without approaching the breaking point of the 
rubber at the weakest place of the tube. Every 
molecule of air which can be safely held in place 
in the tube helps to do the work for which the 
tire is employed. Incidentally, it keeps tube and 
casing in the most desirable form, for which they 
are designed, and holding them rigidly, offers 
stones, nails and other road sundries such resist¬ 
ance as is needed to make the impact harmless. 

Water Injurious to Tires. 

When water works its way beneath the tread 
and breaker strip and into the carcass of a tire 
premature deterioration is certain to follow. 



66 


Autocraft 


When a tire is completed it is free from mois¬ 
ture on the inside and it remains so as long as the 
tread is in condition to perform its full duties. 
However, small cuts, caused by sharp objects in 
the roadway, are very apt to appear, even in a 
new tire, and through these openings water 
eventually finds its way to the tire carcass. In 
time this produces separation of the individual 
plies of fabric of which the carcass is made up, 
and the tire rapidly goes to pieces. Breaks in 
the tread also admit sand and dirt, which cause 
fabric separation. 

When a motorist discovers one or more small 
cuts in the tread of a tire he should close them 
at once. There are several special preparations 
for this purpose which can be easily applied after 
the cut has been thoroughly washed out. The 
expense amounts to practically nothing and the 
saving is bound to be great. 

Tire Pointers. 

Air costs nothing; tires are expensive. 

More tires give out from insufficient inflation 
than anything else. Remember that it is the air 
in the tube that carries the load and cushions the 
road. 

Avoid sudden application of the brake. 

If one side of a tire shows more wear than an¬ 
other, turn it around. 

Running on a tire flat, even a short distance, is 
sure to be costly. 

Better run on the rim, very slowly and care¬ 
fully, if imperatively necessary, and the distance 
is very short, than on a flat tire. 

Keep grease and oil away from your tires and 
tubes always. They destroy rubber. 

The Cause of a Blow-Out. 

No doubt every motorist has had the experi¬ 
ence of the so-called “blow-out.” This experi- 


Care of Tires 


67 


ence affects all in the same way. It is nothing 
but an exasperation, and although a blow-out can 
often be repaired, the motorist cannot help pre¬ 
ferring never to have had it in the first place. 

Today the importance of the automobile tire 
industry has fostered an improvement of the tire 
as now manufactured, to the point that the mo¬ 
torist who cares can, by a few simple precautions, 
protect himself from the blow-out bugaboo. 

A blow-out is due to one of a few simple 
causes, which if given the necessary attention can 
be easily avoided. To prevent the blow-out we 
seek the cause and eliminate it. Accordingly, we 
will show and explain briefly the different causes 
of blow-outs. 

The amount of air in a tire is just as important 
as the tire that contains it. Improper inflation 
renders a tire susceptible to blow-outs, just as 
proper inflation prevents this annoyance. This is 
the reason: 

The body of the tire is of fabric; several plies 
are used and the mass, after being thoroughlv 
impregnated with rubber is vulcanized into an 
integral whole—the tire. Over the body is a layer 
of rubber—the tread. 

What happens when a round stone, a brick, a 
car track, or any blunt object is encountered? If 
the tire is improperly inflated the internal air 
pressure not offering sufficient resistance, the ob¬ 
ject will sink into the tire, forcing it inward at 
this one place. The tread comes into actual con¬ 
tact, but its elasticity allows it to adapt its shape 
so that it usually suffers no injury, unless the 
object be sharp and cuts it. But the effect on the 
fabric is more serious. It isn’t elastic; it can’t 
stretch; consequently, if the object sinks in far 
enough to produce enough strain, it must break. 

Naturally, that ply of fabric receiving the great¬ 
est strain is the inside one, for it undergoes the 


68 


Autocraft 


greatest distortion, and for this reason it is the 
first to break. Seldom, indeed, is any shock vio¬ 
lent enough to break every ply of fabric and cause 
an immediate blow-out. Most always it is only 
the inside ply that is fractured at the time. As 
this isn’t apparent, the tire usually continues to 
give service, but the broken edges of the inside 
fabric chafe the other plies. The natural bending 
of the tire finally breaks the remaining plies, and 
then the tube forces its way through, resulting 
in a blow-out. 

This is the first warning the motorist receives 
that something is wrong. He didn’t know the 
fabric was broken some time before. He sees 
nothing but the immediate conditions, and doesn’t 
realize that his misfortune is something he could 
have prevented if he had only known how. 

The reason the inside ply of fabric broke in the 
first place, was the result of improper air pres¬ 
sure. This permitted the object on the road sur¬ 
face to sink in and stretch the fabric at one place 
to the breaking point. Had the pressure been of 
the proper amount it would not have been pos¬ 
sible for the object to have made such an impres¬ 
sion. The internal air pressure would have of¬ 
fered the proper resistance, and the shock instead 
of being localized would have been distributed all 
over the tire, and so absorbed without injury. . 

Hence the remedy: Use the air gauge, and 

carry the proper pressure. 

Again, the tread has received a cut. Various 
foreign substances from the road surface are 
forced through the cut by the motion of the tire. 
As a result, these impurities have a tendency to 
spread, separating the tread and fabric. This 
opening of the tread lays the fabric bare to road 
wear and the action of sand and moisture. The 
latter rapidly rots the fabric, weakening it until 


Care of Tires 


69 


the pressure can no longer be sustained, and then 
the same aforesaid fatality occurs. 

For this the remedy is repair gum. Cuts re¬ 
paired in time will grow no worse, and so these 
consequences are avoided. 

In conclusion, there are two important causes 
of blow-outs—under inflation, which results in 
the breaking of the plies of fabric, and neglected 
tread cuts. Avoiding these by means of a pres¬ 
sure gauge and a can of repair gum, the motorist 
will be able to avoid the trouble to which they 
lead—the blow-out. 


* 




Cleaning the Car 

Washing. 

W HEN a car is new, wash it with cold 
water, as it will help to set the varnish. 
Luke-warm or cold water are ordinarily 
used in washing the car, but never use hot water, 
it will ruin the painting. 

To remove grease or oil on fenders and wheels, 
some brand of automobile soap (commonly known 
as soft soap), dissolved in water, can be used; 
however, do not use on body, as it affects the 
gloss of the varnish. When purchasing a soap 
of this kind, you can be somewhat safe by inquir¬ 
ing what it is made from. A soft soap made of 
pure vegetable oils, chemically neutral and con¬ 
taining no free alkali, or any other acid or grit 
to bite into fine finishes, is recommended. 

Do not wash the hood when it is warm, as this 
will cause it to lose its lustre. 

Do not rub body with sponge unless necessary; 
it always holds sand or grit. Wash by rinsing 
off as much as possible. 

Do not play a sharp stream of water onto car 
while washing; it will drive small particles of 
sand, miniature stones, etc., into the paint. 

It requires considerable skill to wash a car 
properly without injuring the finish; but the im¬ 
proved appearance makes it well worth the trouble 
Automobiles are subjected to harder service than 
any other vehicle. They are exposed to all kinds 
of road and weather, spattered with grease from 
oiled roads, scratched by flying sand and gravel: 
they are left standing in sun, wind and snow, and 
as a rule no very great care is used in cleaning 
them afterwards. 


( 70 ) 


71 


Cleaning the Car 

The manufacturers spend much time and money 
in giving automobiles a fine finish with a high 
lustre. This finish can be quickly spoiled by lack 
of care, or may be preserved by using proper pre¬ 
cautions. 

Light dust may be blown ofif or removed with 
a feather duster. When necessary to use water, 
let it run slowly from a hose with a sprinkling 
nozzle or no nozzle at all. If a small nozzle is 
used which adds force to the stream, it will drive 
the sand into the finish and soon remove its gloss. 
Dried mud should be removed as soon as possible, 
as it injures the finish. It should never be wiped 
off dry. Soak it with water applied with a sponge 
or a gentle stream from a hose ; after it is softened, 
wash it away carefully. 

Soap is not necessary for removing dust or 
mud. It must be used, however, when the sur¬ 
face is stained with road oil or from some other 
causes. Never apply soap directly to the finish. 
It is much better to dissolve it in water and make 
suds of suitable strength. Any soap, no matter 
how mild or neutral, will injure varnish if left 
standing on it. Dissolving soap in water is much 
safer, and is also more economical, because it does 
not waste the soap. 

Suds made as above will remove all greasy 
stains. 

When through washing, dry carefully with a 
chamois. 

Cleaning of. Nickel-Plated Parts. 

Lamp black or regular silver cleaner paste are 
most frequently used to clean nickel-plated parts. 
Use a soft flannel or chamois to rub with. 

Lamp reflectors can be cleaned with Put? 
Pomade, applied and polished with soft, clean 
chamois. 


Symptoms of Common Troubles 

When the Motor Stops: 

1. Look at gasoline supply. 

2. Wires disconnected. 

3. Not enough oil in motor crank case (will 
be noticed by motor knocking, and finally stop¬ 
ping). 

4. If the motor cannot be cranked, look for 
transmission to be engaged; bearing seized due 
through lack of oil. 

When the Motor Misses: 

1. Defective spark plug. 

2. Insulation broken on wire; wire discon¬ 
nected. 

3. If the motor spits back through carburetor, 
look for dirt in same. Gasoline supply cut off 
from water or dirt in gasoline line. Water in the 
gasoline pipe will sometimes freeze and cut off 
entire flow. 

4. Compression weak in any one cylinder 
valve; push rod or valve sticking. Dirt under 
valve. Valves not seating properly, may need 
regrinding. 

5. When the motor runs and quits, then runs 
again, it is probably due to something like water 
or dirt in gasoline line. 

6. A missing cylinder can be located by open¬ 
ing priming cocks on top of cylinders one at a 
time. If the trouble is not in the spark plug, at¬ 
tention should be given the valve to note if it is 
seating properly as well as opening and closing 
at proper time. The loss of compression will be 
detected by turning motor slowly by hand. Each 

(72) 


Symptoms of Common Troubles 73 


cylinder may be tested individually for compres¬ 
sion by closing all priming cocks excepting one. 
After having tried one particular cylinder, open 
the priming cock in same and turn off another 
in some other cylinder. In this way you will 
have discovered the weakest cylinder. 

7. Worn or blown-out gaskets of intake mani¬ 
fold joints will cause missing. 

Power Loss: 

Motor will run good on level travel, but loses 
power on hill or under heavy load. 

1. Valves not seating properly, causing loss 
of compression. 

2. Spark too far retarded. Ignition late. 

3. Carburetor flooding causing too rich a 
mixture. 

4. Motor running hot through lack of oil or 
water. 

5. Not enough gasoline, probably due to stop¬ 
page in pipe. If the motor spits back through 
carburetor upon sudden opening of the throttle, 
this indicates there is a lack of gasoline. 

6. Tire down. 

7. Weak mixture in carburetor. 

8. Examine brakes. Feel to see if they are 
hot, due probably to dragging. Push car along 
the floor or road by hand and notice if it rolls 
easily. 

Cannot Start Motor: 

1. Examine gasoline supply. 

2. Be sure switch is on. 

3. Weak mixture. 

Don’t fry to change adjustments without know¬ 
ing why you are making them, as it will only 
cause more serious trouble. 


74 


Autocraft 


Don’t get excited. Many an experienced auto- 
ist has cranked his car a few hundred revolutions 
and finally discovered it wouldn’t start because 
the switch was off. 

When the Motor Knocks: 

1. A light knock running at high speed in¬ 
variably indicates a loose connecting rod bearing. 

2. A heavy, dull pounding running at slow 
speed with the motor under load purposes to be 
a loose crankshaft bearing. 

3. A motor laboring on hill or pull, due to the 
motor running too slow on direct drive, will cause 
pounding or knocking. 

4. Carbon knock; excessive amount of carbon 
gathered in cylinders. 

5. A light clicking or tapping sound is often 
contributed to too much play or space between 
valve push rod and valve stem. 

6. A spark knock is often caused by operator 
carelessly advancing same too far. 

Overheating of the Motor : 

1. Water supply too low. 

2. Fan belt slipping. 

3. Gasoline mixture too rich. 

4. Cylinders heavily carbonized. 

A Circulation stopped, due probably to pump 
not working or some stopped up water pipe. 

6. Ignition too late. 

7. Not enough oil in motor. 


What is Horsepower? 


W HAT is horse-power? This question, 
while well understood by engineers in 
general, is a hard problem for the be¬ 
ginner to grasp. Horse-power provides a never- 
failing source of discussion for him. No other 
term in his vocabulary is so misunderstood, or 
has so many interpretations, and at the same time 
it is a subject of vital importance to him, for the 
reason that it affects his comfort, his pride or 
his bank account. 

The purpose of this article will be to enlighten 
him on this subject, and at the same time show 
how the horse-power of an automobile engine 
can be approximated very closely by the A. L. 
A. M. formula, giving an example as well as a 
table. The table comprises cylinder diameters 
of 2 % to 6 and engines having 1, 2 , 4, 6 or 8 
and 12 cylinders. No mathematical data is used, 
to avoid complications. 

The definition of the word “horse-power” as 
applied to a motor car engine is not understood 
by the average automobile owner or driver. 
There are many laymen who think that by horse¬ 
power is meant the average load which a horse 
can pull in continued service. This is not true, 
however, as the pulling power of horses varies 
and no definite point could be reached in this 
way. It is evident that a large horse is capable 
of pulling a greater load in continued service 
than a smaller animal. 

The term “horse-power” was first used by 
James Watt, after numerous tests of the load 
which the average horse could pull in continued 
service and a constant derived therefrom, which 
will be discussed later. 

( 75 ) 


76 


Autocrajt 


Horse-power as a technical term has a very 
definite meaning. It is defined as the rate of 
doing work. Work, in turn, is the product of a 
force and the distance it moves. Thus horse¬ 
power is force times distance divided by time. 
It is expressed in units implying these three 
quantities: pounds, per foot, per minute. One 
horse-power is equivalent to 33,000 foot pounds 
per minute, that is, a power which can lift 33,000 
pounds one foot in one minute, or 1,000 pounds 
33 feet in one minute, or 1 pound 33,000 feet in 
one minute, or 1 pound one foot in 1/550 second. 

In a motor car engine power is developed by 
the burning and consequent expansion of the 
gasoline mixture in the combustion chamber. 
The expansion results in a force exerted on the 
piston head, the travel of the piston on its stroke 
gives the distance, and the number of revolutions 
per minute of the crankshaft adds the time 
factor. Given the pressure in pounds per square 
inch of the cylinder, the stroke in feet or inches, 
and the number of revolutions per minute, the 
horse-power developed in a gasoline motor can 
easily be computed. Although the last two quan¬ 
tities are easy enough to obtain, the first, unfor¬ 
tunately, cannot be had without the use of deli¬ 
cate and costly instruments. 

To determine the power actually developed by 
a motor, numerous methods can be used, but all 
depend upon the absorption and incidental meas¬ 
urement of the power, as by a friction brake, 
electric generator, a water pump or fan. As the 
earliest and best known of these the friction or 
prony brake method may be described. Like all • 
others, it depends upon the definition of force 
times distance divided by time. The application 
is generally quite familiar. A brake band or 
shoe is applied to the fly-wheel and prevented 
from rotating with the fly-wheel by weights at- 


What is Horsepower 


77 


tached to the end of the lever arm attached to 
the brake band. The weight or the length of 
the lever arm is adjusted until the weight is in 
equilibrium, tending neither to rotate with the 
fly-wheel or to drop under the force of gravity. 
The weight then gives the force, the length of 
the arm the distance, and the number of revolu¬ 
tions the time factor necessary for calculating 
the horse-power. 

In many automobile plants where motors are 
made in large quantities, the run in test is re¬ 
garded as a necessity and it is a simple expedient 
to attach a fan to the fly-wheel in place of the 
clutch, and, if the fan is properly devised, it will 
limit the speed of the motor to that which should 
obtain in actual service, when the motor is doing 
its accustomed work. The fan requires no atten¬ 
tion; it offers a constant resistance, so long as 
the speed of the motor is maintained constant, 
and if the speed changes do creep in they will 
indicate that some adjustment is necessary to 
either mixture or ignition system, but there will 
be no damage done, even if the adjustments are 
not made. This form of dynamometer is eco¬ 
nomical; it takes up almost no added space, and 
it is, in first cost, at the bottom of the list. In 
some instances this fan dynamometer has been 
fitted with a tachometer, by means of which the 
power delivered may be noted by ascertaining 
the speed and comparing it with a chart of power 
for speed as determined by previous calibration. 

In large automobile factories the balanced 
electric system seems to have considerable ad¬ 
vantage. There may be a number of sets of 
these machines, and all that is required to satisfy 
conditions is to have the machines in pairs. One 
machine (of each pair) is driven by an engine 
as a dynamo, which furnishes current to the 
other, which as a motor drives the second engine 


78 


Autocraft 


which is getting its “run in” test. The dynamo 
loads the engine which furnishes the power, 
which is electrically transmitted to drive the 
second engine, which is being run in during this 
period of time. 

There is still another possibility. If the en¬ 
gine to test is connected to a centrifugal pump 
and the pump in turn by piping to a reservoir, 
the power required to pump the water to the 
reservoir may be adjusted to equal the ability 
of the motor to be tested and the work done 
in the process turned to good account. 

It should be understood that the motor testing 
question has other angles besides the one which 



is being considered here; investigations of the 
internal conditions are also taken into account. 

Obtaining the cylinder pressure in pounds per 
square inch, that is, the force exerted upon the 
piston by the expansion of the gas, unfortunately 
cannot be obtained without the use of delicate 
and costly instruments, as mentioned above. 
For this reason a formula was adopted by the 
Society of Automotive Engineers, which is 
termed the S. A. E. formula, and which was 
intended to approximate the horse-power of 
automobile engines very closely. This formula 
received such a favorable reception by both 
manufacturer and user that its continued use 
has been assured. Before its appearance there 
had been a long-felt need of some connecting 










































What is Horsepower 


79 


link between the size and probable capacity of 
the various motors. Most objections to this 
formula are based upon the idea that it is to 
determine once and for all the power which a 
given motor is capable of developing. This is 
not true, as the horse-power of a gasoline engine 
cannot be computed exactly from its dimensions 
by any formula whatsoever, no matter how intri¬ 
cate and learned in appearance. 

The principal feature considered in this for¬ 
mula is simplicity, and this is an unquestionable 
advantage. It would be impossible to simplify 
it any further and still obtain the least approach 
to the horse-power rating. There is, however, 
one short cut, which might not appear to the 
layman. For instance, the formula reads: H. P.= 
, which in reality is the same and equal to 
H. P.=.4 D 2 N, as will be explained later. 

In the formula— 

D = Diameter of cylinder in inches. 

N = Number of cylinders. 

2.5 is a constant based upon a mean ef¬ 
fective pressure of 70 pounds per 
square in. and a piston speed of 1,000 
ft. per min. 

D 2 is read as the diameter squared, and to 
square any number is to multiply it by itself; 
that is to say, the square of 2 is equal to 2X2=4, 
or 4X4=16, or 16X16=256. Likewise any 
number multiplied by itself will give the square 
of that number. 

In using the formula, remembering that the 
power of a motor is in proportion to the square 
of the cylinder diameter, the formula may be 
written as follows: 

Horse-power = Diameter of cylinder in inches 
squared, multiplied by the number of cylinders 
contained on the engine and divided by the con- 



80 


Autocraft 


slant 2.5; or to transpose the formula, Horse¬ 
power = .4 times the diameter of cylinder in 
inches squared, multiplied by the number of 
cylinders. 

Citing, for example, a four-cylinder motor with 
a cylinder diameter of four inches, and proceed 
to calculate the horse-power of the engine. 

H. P— =25.6 or .4X4X4X4=25.6 

For six cylinders, four-inch cylinder diameter— 

H. =38.4 or .4X4X4X6=38.4 

And again for an eight-cylinder engine— 

H. P.=jj£s* =51.2 or .4X4X4X8=51.2 

And for twelve-cylinders— 
fx^=76.8 or .4X4X4X12=76.8 

Using precisely the same method the horse-power 
of any motor (according to this empirical for¬ 
mula) may be approximated. Still further con¬ 
venience may be had by the use of a table such 
as the accompanying one, especially for fractional 
values of the bore. This table is in the main 
self-explanatory, but a few features may be 
pointed out. The values are given so close to¬ 
gether that intermediate values may be found by 
interpolation. Thus 4 Vi 6 mc h is half-way be¬ 
tween 4 and 4*4, and consequently the power of 
a 4 x / 16 -inch four-cylinder motor is between that 
of a 4 and 434-inch motor. 

For example, we will take these three cylinder 
diameters in order to show the interpolation is 
carried out. We must first find the difference 
between the 4 and 434-inch motors. Referring 
to the table, a 434-inch four-cylinder motor is 
rated at 27.20 H. P., while the 4-inch is rated at 
25.60 H. P. Now, substracting this from the 
former, we get 1.60 H. P. Half of this sum 
added to the power of the 4-inch motor will 
give us the power of 4 1 / 16 -inch motor, thus: 







What is Horsepower 


81 


SA- E. //o/TSy: - f^o yvfsr 7#&L£r. 

330/8/7 

c‘Y///y/d3:/?s 

/ 

<2 

4 

& 

<5 

72 

276 

£ 0 Z 

4.03 

8/0 

/ 2 /3 

/6.zo 

2430 

2% 

2.23 

44/ 

9.02 

73.32 

78-03 

270 7 

2/e 

£.<ro 

JoQ 

70.00 

/3o o 

£0.00 

30.00 

2-% 

20 3 

3.66 

7723 

/683 

224/ 

3364 

2% 

3. o£ 

6 o4 

72.08 

70/3 

24/6 

3624 

2% 

3 34- 

666 

7337 

20. oo 

26 74 

40.// 

3o 

3Co 

72o 

7440 

2/60 

2888 

43.20 

3ft 

3 9/ 

7-8 a 

7464 

£33o 

3/28 

46.92. 

3ft 

4.2.3 

846 

7692 

23.09 

3394 

30.8/ 

3% 

4J7 

3/0 

78.27 

2730 

3642 

3463 

3f6t 

49 0 

380 

7467 

2944 

39.22 

3883 

3^ 

32 7 

70 34 

2708 

3737 

42/6 

63.24 

3% 

3-62. 

//23 

22.30 

3373 

4400 

67-30 

3 r /s 

6. 0 3 

72// 

24.22 

3632 

4844 

7866 

4. O 

6 40 

72.00 

23.60 

3640 

3/20 

7680 

4'ft 

68 0 

7360 

£7.20 

408o 

3440 

8/60 


723 

74-30 

29. oo 

4340 

38.00 

6708 

4*ft 

70 6 

73732 

S O 63 

46.00 

6730 

9793 

4ft 

6/o 

7620 

3£4o 

4860. 

6480 

9720 

4% 

637 

/ 7 74 

3428 

374/ 

6836 

70284 

4ft 

9. 03 

78-07 

9673 

4420 

7230 

708.43 

4ft 

930, 

73.72 

38-23 

372/ 

7630 

/7473 

>3.0 

/oo o 

20.00 

48.00 

<60.00 

<94.00 

720. O0 

3'ft 

70 33 

2/70 

4220 

6320 

3420 

726 40 

3'ft 

7/0 3 

22/0 

442o 

<6646 

8840 

73260 

3% 

//38 

23/7 

4634 

6930 

92.68 

739.02 

Sft 

/£ /£ 

2424 

4848 

7272 

9696 

743/44 

3'% 

/£ 70 

23.40 

3000 

76./O 

/O/60 

73240 

3% 

73 23 

2630 

3300 

79.30 

/ 06 oo 

739\00 

<3% 

7 38 / 

£763 

43.28 

82.88 

7/036 

76338 

- ~STB 

7440 

28 83 

3770 

8464 

//3.40 

773/0 


Fig. 35. 










































































82 


Autocrajt 



I //////////////////y 




















































































































What is Horsepower 


83 


1.60-r-2+25.60=26.40 H. P. In precisely the 
same manner any other size in between those 
listed can be found. 

As horse-power by this formula is propor¬ 
tional to the square of the cylinder diameter, 
doubling this multiplies by four and halving it 
divides by four. Applying this to the table, the 
power of a two-inch cylinder will be one-fourth 
of the power of a four-inch cylinder, and the 
power of a seven-inch cylinder will be four times 
that of a 3p2-inch or 19.60 H. P. 

As a final criticism of the formula, and a warn¬ 
ing against it's too confident use, it will suffice to 
state that it tends to overrate small motors and 
underrate large motors. This really makes very 
little difference, for no one is interested in a 
close comparison of a three-inch and a six-inch 
motor, as he is of one more nearly the same size 
and within the variation of an inch or so in the 
diameter, the formula is very reasonably accu¬ 
rate. Empirical formula will avail up to a cer¬ 
tain point and within certain explored limits. 
In a motor, for illustration, the formula will 
work very well, indeed, if the cylinder diameter 
is within the domain found to conform to the 
conditions which rendered the formula possible. 


The Steering Gear 


O NE of the essential features of a motor car 
is the method by which it is controlled, 
and the most essential element of control 
is the steering gear. The requirement of an 
automobile steering gear is radically different 
from those of other vehicles. 

Horse-drawn vehicles are ordinarily steered 
by means of a fifth wheel attached to the for¬ 
ward unit of the vehicle gear which pivots on 
what is known as the king bolt; however, the 
divided axle is universally employed on all self- 
propelled vehicles. This was described in an¬ 
other chapter on “Front Axles/' and this ar¬ 
rangement of pivoting the wheels is known as 
the Ackerman steering gear. 

With a fifth wheel the leverage is obtained by 
a tongue or pair of shafts, while motor car front 
wheels are pivoted independently, as pivoting 
the front axle would involve serious complica¬ 
tions, as in thrusting one or the other of the 
front wheels over the road at a rate of speed 
faster than the onward movement of the vehicle 
on a rough road would require considerable 
effort. 

Technically, the Ackerman steering gear has 
been revised, and at present it is based upon the 
principle that if the vehicle is to turn a corner 
without lateral slip of any of the wheels, the 
steering linkage must be so arranged that axis 
of all wheels produced always intersect a com¬ 
mon vertical line, this vertical line forming a 
momentary axis of rotation. 

As the front wheels are pivoted independent 
of the front axle, which remains stationary, they 

(84) 


Steering Gear 


85 


must be connected by a tie-rod through levers 
mounted on the knuckles or pivots, while a con¬ 
nection with the steering mechanism must also 
be made. This connection is termed the steer¬ 
ing-arm connection and sometimes is referred 
to as the drag link. 

The Steering Mechanism. 

Motor cars are steered by means of a hand- 
wheel mounted at the upper end of a steering 
column. This wheel is mounted on a spider, 
which is secured to a shaft passing through the 
column or outer tube, often termed the mast. 
At its lower end this shaft enters a housing, 
which houses a steering mechanism, to reduce 
the motion of the hand-wheel. This mechanism 
may consist of either a rack and pinion, bevel 
pinion and sector, worm and sector, or a screw 
and nut. The steering column is generally 
styled according to the type of steering mechan¬ 
ism. This mechanism must always consist of 
two members, one of which is attached to the 
steering shaft, while the other is attached to an¬ 
other shaft which carries the steering arm. 

It is now general practice to make the steering 
mechanism back locking or irreversible, as the 
forces acting on the road wheels act as a dis¬ 
advantage upon the operator’s hands. 

Steering mechanisms are made irreversible by 
so arranging them that they operate freely when 
turning the hand-wheel, but require a consider¬ 
able force to turn the wheel through the reduc¬ 
ing mechanism, as in striking obstacles on the 
road surface. 

Drag Links and Tie-rods. 

Drag links and tie-rods are usually of the 
same proportions and the general practice is to 
provide the former with springs to absorb some 
of the shock which is transmitted to the steering 


86 


Autocraft 



mechanism. There are various types of steering 
mechanisms and drag links employed at present, 
and in this chapter will be found illustrations 
and descriptions of all well-known types. 

Component Parts of the Steering 
Mechanism. 

Fig. 37 gives a general idea of a complete steer¬ 
ing arrangement of all passenger cars and rep¬ 
resents conventional practice. 


Fig. 37.—Component parts of the complete steering mechanism 

of a motor car. 

In this illustration, 1 is the hand wheel; 2, the 
steering shaft; 3, the column mast; 4, the hous¬ 
ing, which houses a worm and sector mechanism: 
5, the steering arm; 6, the drag link; 7, the front 
axle; 8, the steering knuckle and lever; and, 9, 
the tie-rod. These parts go to make up a com¬ 
plete steering unit, and while various types of 
mechanisms may be used, they must be con- 









Steering Gear 


87 


nected as shown for fore and aft steering, while 
for cross-steering the drag link would be con¬ 
nected at some point on the tie rod, being retained 
parallel with the tie rod. The steering gear be¬ 
ing so mounted as to give the ball arm a cross¬ 
wise instead of a fore and aft movement. 



Fig. 38.—Bevel pinion and sector steering mechanism used 

on the Reo cars. 


Bevel Pinion and Sector Type. 

Fig. 38 depicts this type of steering mechanism, 
which is used on the Reo cars. In this case the 
steering shaft is made solid, while the usual 
hand wheel and spider are secured to its upper 
end. The lower end of this shaft carries a bevel 
pinion which meshes with a sector having bevel 































































88 


Autocraft 


teeth and attached to a horizontal shaft carrying 
the steering arm. Steering motion is limited by 
leaving a portion of the sector without teeth, and 
the end thrust of this sector is taken by a steel 
roller, supported by a spring to maintain it in 
contact with the sector. 



The spark and throttle levers are mounted on 
opposite sides outside the column and are con¬ 
trolled by means of frictional members and 
springs located below the footboards. This type 
of mechanism has less need for a housing than 
other types and is also completely reversible. 

The Worm Type. 

The worm type may either consist of a worm 
and sector or a worm and wheel. Fig. 4 illus- 










Steering Gear 


89 



Fig. 40.—Worm and Sector Type of Steering Gear. 

steering gear, which is of the worm and sector 
type. The gear is shown in section, and it will 
be noted that the ball arm which gives motion 
ro the steering connection is mounted upon a 


trates the latter type, which is made by a promi¬ 
nent parts maker and used on a number of 
vehicles, and is representative of modern worm 
and wheel practice. Fig. 5 illustrates the 






90 


Auto craft 


horizontal shaft, “L,” which also carries the 
direction, depending upon the direction of rota¬ 
tion of the steering wheel. The ball arm, of 
course, moves in unison with the sector, since 
they are mounted upon the same shaft. 

The steering shaft is hollow so that the carbu¬ 
retor and spark control shafts can pass through 
it. Ball thrust bearings are mounted on each 
end of the worm, which take the thrust in steer¬ 
ing. Turning the steering wheel rotates the 
worm, which in turn moves the sector in each 
sector, “E,” meshing with the worm, “D,” mount¬ 
ed upon the steering shaft, “F” and “G,” form 
an adjustment for wear, while ‘H” and “J” are 
adjustable stops for controlling the movement 
of the sector. “B” is a bearing lock, while “A” 
and ‘C” are removable plugs to permit th^ : n- 
sertion of lubricant. 

This gear is termed an irreversible type, 
as the ratio of the worm diameter to that of 
the sector gives a considerable leverage to turn 
the wheels, while the forces acting at the road 
wheel act as a mechanical force on the sector; 
however, as in this case the leverage is reversed, 
considerable force must be applied in order to 
turn the steering wheel. 

The Screw and Nut Types. 

It is a well-known fact that a screw when 
rotated with a nut which is constrained 
from turning, but capable of sliding, can move 
the latter with a slight effort, but no ordinary 
force applied to push the nut is capable of turn¬ 
ing the screw. The above arrangement consti¬ 
tutes a form of irreversible steering mechanism 
which is also quite popular. Designs differ in 
detail, principally in the manner of imparting 
motion to the horizontal shaft carrying the steer¬ 
ing ball arm. 


Steering Gear 


91 


Fig. 41 depicts the Ross screw and nut steering 
mechanism, which is quite popular on commer¬ 
cial vehicles, as its design is based upon the prin¬ 
ciple that immense wearing surface is better than 
adjustment. The hollow steering shaft carries 
a steel screw at its lower end, mounted between 
two ball bearings to take its end thrust. This 
screw has a single thread of considerable length 
which is entirely enclosed by a carbon steel nut. 



When the hand wheel is turned this nut is given 
lateral movement, as it is of square section and 
is thereby prevented from turning. On each side 
at the lower end of this nut cylindrical recesses 
are turned, and cylinders, which are free to 
rotate, are placed in these recesses. The cylin¬ 
ders have slots milled in them which receive a 
pair of arms projecting from the horizontal shaft 
carrying the steering ball arm. 

The Jacox steering gear is also of the screw 
and nut type, but differs in several ways. This 














92 


Autocrajt 


gear has a substantial steel worm enclosed by a 
semi-steel nut which is split lengthwise into two 
halves. The worm is double-threaded both right 
and left-hand, so that in turning the hand wheel, 
one-half of the nut rises while the other falls. 
The horizontal shaft which carries the steering 



ball arm has a rocking arm forged integral with 
it and the ends of the half nuts bear upon it. 
A ball thrust bearing is mounted at the upper 
end of these half nuts, which is so arranged 
that its adjustments take up all wear. 

Drag Links. 

Fig. 43 illustrates a popular type of drag link 
or steering connection, which has springs at both 
ends to absorb shock, each end being provided 
























93 


Steering Gear 


with an adjustment to take up spring tension 
and wear. These are generally made of tubular 
section for lightness and have electrically welded 
ends. Steering joints are usually enclosed in 
leather boots and packed with grease, which pre¬ 
vent dirt and grit from cutting the ball surface. 
The ball joints are universal in action and are 



Fig. 43.—Conventional Type of Drag Link Steering Gear. 


necessary at both ends of this member because 
the steering arm moves in a vertical plane and 
the steering knuckle on the axle moves in a hori¬ 
zontal plane; however, instead of these ball 
joints, fork joints are sometimes used. The lat¬ 
ter are more simple and present larger wearing 
surfaces. However, they are m®re difficult to 
enclose and cannot be made adjustable. 

The steering mechanism requires very little at¬ 
tention. Of course, all grease cups should be 
given a turn every day or two, depending upon 
the mileage, and they should be filled every week. 
Adjustments should be made promptly as condi¬ 
tions demand, and all parts should be examined 
thoroughly at least once during the season. 




















How to Oil an Automobile 

Proper Attention to Details of Lubrication 
Will Save Time, Repairs and Reduce 
the Upkeep of Motor Cars. 

Motor. 

M ANY different systems are employed to 
lubricate motor car engines, however, re¬ 
gardless of the method employed, they 
practically all require the same attention. It is 
considered good practice and generally recom¬ 
mended, that the motor oil be changed every 500 
to 1000 miles and to always retain the proper 
level in the crankcase. Insufficient oil is dan¬ 
gerous and poor economy. Lack of lubrication 
will score the cylinders and ruin the bearings. 
Oil should be kept in a clean tank and always 
filtered before using. The measures or can used 
in replenishing the motor supply should always 
be thoroughly cleansed before using. 

It pays in the long run to use the best quality 
of lubricants. Money saved by buying cheap 
oils will be lost in worn-out bearings or cylinders. 

Valves. 

Valve levers, guides and other working sur¬ 
faces of the valves operating mechanism, if not 
oiled direct from the lubricating system, should 
have a few drops of oil every few days, depend¬ 
ing upon the amount of mileage. 

Magneto. 

A magneto should be oiled about every 1000 
miles. Never use a heavy oil; the proper lubri¬ 
cant is a very light sewing machine oil. A few 
drops is all that is necessary. Be careful that 
lubricant does not reach any other part of the 

(94) 


How to Oil an Automobile 95 

instrument, except oil holes provided for this 
purpose. 

Electrical Units. 

The various parts of the electrical equipment 
will require a few drops of light machine oil 
every 500 to 1000 miles at certain points, depend¬ 
ing upon the system employed, while others will 
require grease. The instruction book supplied 
with the car should be consulted as to the proper 
lubricant and procedure. 

Universal Joints. 

If leather boots are used as universal joint dust 
covers they should be securely fastened in place 
again after lubricating. A heavy grease or mix¬ 
ture of graphite and heavy oil are used. These 
joints are usually reached by removing the floor 
boards. 

Transmission. 

There are a number of standard gear com¬ 
pounds on the market. Whatever is used, the 
combination should be of such consistency that 
it will follow the gears when they are in motion. 
It has been found that a steam engine cylinder 
oil, sold under the name of “600 W,” is a good 
gear lubricant, especially if mixed with a little 
flake graphite. 

Another good mixture frequently employed is 
two-thirds ordinary cup grease and one-third gas 
engine cylinder oil, mixed with a little graphite, 
which works very well. Fresh oil should be re¬ 
plenished about every 1,000 miles. When you 
have run 3,000 miles completely remove all old 
oil, and replenish with a fresh lubricant. 

Front Axle. 

The front axle spindle bolts are usually sup¬ 
plied with grease cups and should be given a turn 


96 


Autocrajt 


every 250 miles. To thoroughly lubricate these 
bolts, jack up car and swing the wheels back and 
forth, working the grease where friction occurs 
in the bolts. 

Like the spindle bolts, grease cups are generally 
provided on front axle distance rod and should 
receive occasional lubrication by turning down the 
grease cups. If the front wheels are equipped 
with roller bearings they should be cleaned an>3 
repacked with fresh grease about every 2,500 
miles. 

Steering Gear. 

Grease cups are usually placed in the housing 
of steering gears for shaft, also sector and pinion 
shaft. These should be given a turn about every 
500 miles. If oil cups are attached, oil same 
frequently. Steering gears usually have adjust¬ 
ments to take up back lash or looseness, and 
should be kept free from same. 

Brake Mechanism. 

All brake rod clevis pins and connections should 
be oiled daily. In the event that brake rod pins 
are to be removed to make adjustments, you will 
find that you are well repaid by regular oiling, 
for these pins rust easily and are almost impos¬ 
sible to remove at times from neglect of oiling. 

Springs. 

Springs are usually provided with grease cups 
at both ends and should be screwed down about 
every 25 miles. The spring shackles should not 
have any appreciable amount of side play between 
the ends of springs and their bearings in bracket 
or chassis of frame, since a small amount of end 
play will cause a disagreeable rattle in these 
shackles. 


Hozv to Oil an Automobile 


97 


Springs when assembled are lubricated with a 
mixture of graphite, which is applied to the fric¬ 
tion part of the leaves. When the springs •be¬ 
come dry they will squeak badly, and this can be 
remedied by jacking up car and forcing graphite 
and oil between the leaves while they are partly 
open. In jacking up the car, place the jack un¬ 
derneath the frame, so as to let the axle hang 
free, which will spread the spring leaves some¬ 
what. 

Clutch, Oil Pump, Fan Bearings, Etc. 

In regard to oiling clutch, etc., instructions 
should be carefully followed concerning the par¬ 
ticular make car you operate, and this informa¬ 
tion is usually supplied by the manufacturer of 
the car. 


The Care of Axles 

♦ 

i 

Rear Axle Appendix. 

T HE following brief description of the char¬ 
acter and functions of a differential is in¬ 
serted for the benefit of those readers who 
may be unfamiliar with this exceedingly important 
part of the motor-car. 

The differential consists of a set of bevel gears 
located at the center of the rear axle. Its purpose 
is to divide the power transmitted from the engine 
equally between the two wheels, and to do this in 
such a way that one wheel may revolve faster than 
the other when necessary, as in turning corners 
at high speed. 

In a wagon the rear wheels are mounted on a 
dead axle and revolve independently of each other. 
There is, therefore, no need for a differential. In 
a power-driven vehicle the rear wheels must still 
revolve independently and yet each must receive 
one-half of the power transmitted through the 
rear axle. 

To illustrate the principle in as simple a man¬ 
ner as possible we show in Fig. 44 an experiment¬ 
al apparatus in which A-A’ are the two live axle 



























Care of Axles 99 

shafts to whose outer ends are fastened the wheels 

w—w\ 

Mounted on the inher ends of the shafts A—A’ 
are the bevel gears G—G\ Surrounding these 
gears and concentric with them is a belt-driven 
pulley B. 

It will be clear that if we connect the two gears 
solidly by the rods R—R\ which in turn are se¬ 
curely fastened in the web of the pulley B, move¬ 
ment of pul-lev B will cause both the gears G—G’ 
to revolve at the same speed in the same direction : 
and, since the wheels W—W’ are, like the gears 
G—G\ secured to the shafts A—A’, the wheels 
will also revolve at the same speed in the same 
direction. 

Now, to allow the wheels W—W, and, there¬ 
fore, the gears G—G\ to revolve at different 
speeds, we remove the rods R—R’ binding the two 
gears together and substitute for these rods the 
pinions shown in Fig. 45. These pinions rotate 
freely on the web of pulley B and their teeth are 
in mesh with the teeth of the bevel gears G—G\ 

It is clear that when the pulley B revolves, its 
motion is transmitted through the pinions to the 
gears G—G’ and on through the axles A—A’ to 
the wheels W—W’ just as it was transmitted in 
the apparatus shown in Fig. 1, but with this im¬ 
portant difference—if wheel W is now prevented 
from revolving, the pinions will rotate on the web 
and thus allow the gear G’ to revolve, carrying 
with it axle A’ and wheel W\ 

If gear G revolves slowly, gear G’ can revolve 
rapidly, or vice versa, because the difference in 
their motion is compensated for by the rotations 
of pinions P—P’. 

It will also be clear that in all cases, the pres¬ 
sure transmitted from the pulley B through the 
pinions P—P’ to the teeth of the gear G and the 
gear G’ will be equal, because the distances be- 


100 


Autocrajt 



tween the centers of the pinions and the teeth of 
both gears are always equal. 

In the simplest language possible, when gear G 
remains stationary, gear G’ and the pinions roll 
around, as it were, on gear G, the teeth of the 
pinions pressing forward on the teeth of gears G 
and G’ with equal pressure. 


Referring now to Fig. 46 we see the differ- 








































Care of Axles 


101 


ential as actually used in the rear axle. In place 
of pulley B in Figs. 44 and 45, we have the driv¬ 
ing gear D, and instead of two pinions there are 
now four, but the action is the same as that 
described for the apparatus in Fig. 45. 

The driving gear D receives the power from a 
beveled gear known as the driving-pinion, the 



Fig. 47.—Pouring oil into the differential housing. 


latter being at the rear end of a “pinion-shaft” 
coupled with the main propeller shaft which trans¬ 
mits the power from the engine. 

Lubrication. 

Grease-cups are provided at every moving sur¬ 
face. They are shown on the diagrams and are 
readily found on the axles themselves. 



















Timken Detroit Rear Axle. 

Fig. 49.—This shows you some of the important features of a Rear Axle. 


















104 


Auto craft 


Make certain that every grease-cup is ivell filled 
with a high-grade, light grease, positively free 
from acid and from grit. Care in turning up the 
cups regularly cannot atone for oversight in not 
filling a cup with grease . 

Keep your supply of grease in a tightly-covered 
can so that no grit or dust can get into it. If, by 
any chance, grit does get into the bearings or gears, 
the only thing to do is to wash them out thoroughly 
with kerosene and dry them; after which, clean 
grease should be applied. 

In the rear cap of the differential housing is 
a plugged hole. Remove the plug and pour 
heavy oil in through the hole until it begins to 
come out. You will then have just the right 
amount of lubricant and can replace the plugs. 

Specific directions as to how often to turn up 
the various grease-cups in order to force grease 
into the moving parts are impossible, because the 
periods of time will vary according to the amount 
of use of the car. 

It is even impracticable to direct that one turn 
of the cup should be given every so many miles 
of travel, because so much depends on the grade 
of the grease and on conditions of weather and 
load. 

There is just one simple rule to follow, viz.: 
force the grease forward in small amounts often, 
rather than in large quantities seldom; and err 
on the side of too much rather than too little. 
Grease is cheaper than bearings or gears. 


Motor Car Brakes. 


A MOTOR vehicle, which has been set in 
motion, must be brought to a state of 
rest under varying conditions, and this 
is invariably accomplished in absorbing the en¬ 
ergy of the vehicle by friction. This friction is 
obtained by bringing a band which is held 
stationary into frictional contact with some 
revolving part of the vehicle. The motor car is 
essentially a high-speed vehicle and requires 
powerful and dependable brakes for its opera¬ 
tion. The drum type of brake is most generally 
used. This consists of steel drum secured to 
either the road wheel or some other revolving 
part of the driving units, such as the propeller 
shaft and an expanding or contracting member 
secured to the vehicle frame or axle housing 
which can be brought into contact with brake 
drum. The energy dissipated in heat at the 
friction surface of the drum is withdrawn from 
the kinetic energy stored in the moving vehicle, 
and the speed of the vehicle decreases as its 
store of kinetic energy is depleted. 

There is little uniformity in brake construc¬ 
tion, except that certain states have laws which 
specify that these vehicles must be equipped 
with two brake systems, one for ordinary use 
and the other for emergency purposes. 

Brake Location. 

The brakes may be fitted to either the front 
or rear wheels. The rear wheel position pos¬ 
sesses an advantage, in that, as a rule, the rear 
wheels support much more of the weight of the 
car and the load than the front wheels, and since 

(105) 


106 


Autocrajt 


the braking power depends upon the adhesion of 
the wheel to the road surface, which is dependent 
upon the weight carried, it can readily be seen 
that these possess a greater limiting power than 
the front wheels. The rear wheel position also 
greatly simplifies the brake operating mechanism. 

In shaft-driven vehicles both sets of brakes 
may be located in the rear wheels, or one set 
may be so located and the other may be arranged 
to act on a drum located at either end of the pro¬ 
peller shaft. The latter location possesses a dis¬ 
advantage, in that the reaction due to the fric¬ 
tional force on the brake drum takes place a 
considerable distance from the rear wheel, and 
the closer the application of the braking force 
the fewer parts are subjected to strain. With the 
transmission location, this strain must be trans¬ 
mitted through the propeller shaft, universal 
joint, bevel gears, axleshaft and hub connec¬ 
tions. One advantage of this location is that, 
since the force is multiplied by the rear axle re¬ 
duction, a great retarding effect can be produced 
with little effort. 

Arrangement of Brakes. 

One set of brakes is generally designated as 
the service brake and is intended for all ordi¬ 
nary occasions. This is generally operated by 
a foot pedal lever, as this permits the operator 
to keep one foot on the brake pedal all the time, 
which enables him to operate it without much 
effort. The other brake is called the emergency 
and intended for use when the service brake 
fails or when an exceeding great braking action 
is required. This is most generally operated by 
a lever at the driver’s side, or in some cases by 
a foot pedal having a ratchet lock. 

g Brake Location. 

There are two arrangements of double rear 


Motor Car Brakes 


107 


wheel brakes, which are in practical use, viz., 
two internal brakes acting on the same drum, 
one internal and one external acting on the same 
drum. When a transmission brake is used, but 
one set is placed on the rear wheels, and this 
is usually of the internal type. 

Types of Brakes. 

There are two general types of brakes, the 
band and shoe types, and either may be made 
expanding or contracting. The band type con¬ 
sists of a continuous steel band having a fabric 
frictional facing such as raybestos, multibestos, 
non-burn, etc., while the shoe type may either 
be of cast-iron or bronze, with cork inserts, as 
it may be provided with a fabric frictional facing. 

These shoe type brakes may also be used with¬ 
out facings or cork inserts, but in this case they 
are provided with diagonal grooves to prevent 
chattering and squeaking. 

The drums are invariably made of pressed 
steel, as this reduces the weight to a minimum 
as well as the cost. They are usually bolted to 
the wheels and in some cases form the rear 
wheel hub flange. This also applies to the trans¬ 
mission brake; however, in this case they must 
be bolted to the universal joint hub. 

Double Internal Brakes. 

4 

Fig. 50 illustrates a double internal brake 
which is used on a number of motor cars. It is of 
the shoe type, provided with a frictional lining. 
These shoes are made in halves and are hinged 
to a spider riveted to the rear axle housing 
which forms the stationary member. The other 
end of the shoe rests on a cam, which when 
operated by the pedal causes the shoes to ex¬ 
pand and to grip the brake drum through fric¬ 
tional contact, creating a retarding force on the 
wheels. Springs are used to hold the shoes in 


108 


Autocrajt 


contact with the cam and the hinge, while the 
facing is riveted to the periphery of the shoes. 
These brakes are located side by side and the 
brake spider has a pressed steel disc riveted to 
it, which completely encloses the brakes. No 
adjustment is provided, so the brake linkage to 
the pedal must be relied upon to take up the 
wear of the facing. 



The Internal and External Brake. 

This type (Fig. 51) is also used by a number 
of popular-priced cars. However, the construc¬ 
tion of the internal brake is somewhat different 
from that described above. Instead of shoes, a 
continuous band is employed which has a fric¬ 
tional facing riveted to it and also brackets which 








Motor Car Brakes 


109 


bear against a pin extending from the brake 
spider which acts as the anchorage. Two small 
toggle levers are attached to these brackets, 
which connect with a large link operated by the 
brake lever. The external brake is also of the 
continuous band type; however, it operates on 



the external side of the drum and is made con¬ 
tracting instead of expanding. It is operated 
through a toggle connection with the brake lever. 
In this construction adjustment must also be 
made in the brake linkage. 

Adjustable Brakes. 

Fig. 52 illustrates the internal and external 
brakes used on the White motor cars, which are 
provided with an adjustment for taking up wear. 
The internal brake is operated by a cam, while 
the external is operated through a toggle linkage. 




















110 


Autocrajt 


The cam for operating the internal brake bears 
against two hardened steel members, “B,” which 
may be adjusted in or out and locked by the 
screw, “A,” while screw, “C,” is used to equal¬ 
ize the clearance at either end of the brake 
drum. The adjustment of the external brake is 



Fig. 52.—White Internal and External Brakes, provided with 

Adjustment. 


quite simple. This is accomplished by adjusting 
the screw “F” to give the proper clearance at the 
anchor and raising or lowering the jam nuts “D” 
until the band has proper clearance, then the 
wing nut permits proper adjustment. 

Transmission brakes are usually of the exter¬ 
nal contracting type, and an excellent example 
of this is shown in Fig. 53. The brake drum 
is bolted to the universal joint hub at the rear 
end of the transmission. The brake is of the 
band type with a fabric frictional facing, although 
it may also be of the shoe type. This brake is 
anchored to and supported from the gear box, 































Motor Car Brakes 


111 


which also supports the brake pedal. The knurled 
screw “A” provides an adjustment for taking up 
wear. 

Brake Adjustments. 

Brake adjustments are necessary, as the fabric 
facing material wears in the course of time. In 
some cases this is provided in the mechanism 
used to contract or expand the brake, while in 



Fig. 53.—Transmission Brake. 


others the adjustment is incorporated in the 
brake-rods or pedal connections. 


Brake Equalizers. 

Brakes on opposite wheels must produce equal 









































112 


Autocraft 


retarding, for with unequal retarding effects the 
car has a tendency to skid. In order to accom¬ 
plish this equal retarding effect on rear wheel 
brakes, it is necessary to apply equal operating 
forces. This necessitates an equalizing device 
in the brake operating linkage, which usually 
takes the form of a balance lever. The balance 
lever or equalizer consists of a flat piece of steel, 
having a brake-rod connection from each wheel 
attached to its ends, while a connection from the 

Service-brake 
center rod 
Sendee-brake 
equalizer 
Service-brake rear rod 
Emergency-brake 
rear rod 


Fig. 


pedal is attached at the center. This is sometimes 
termed a whipple-tree equalizer. A modified 
form of whipple tree equalizer is shown in Fig. 
54, being connected with the brake levers. With 
a transmission brake it is not necessary since the 
differential take care of the equal distribution. 



Emergency-brake 
cantor rod 

Emergency-braka 
rear rod 

Servlce-braka rear rod 


54.—Modified Whipple-tree Equalizer. 








The Carburetor 


C ARBURETION is a term not usually clear 
to the lay mind. This may be defined as 
the vaporization of the fuel and the mixing 
of gasoline and air in the proper proportion to 
produce the explosive mixture drawn into the 
cylinders. 

The proportion of gasoline and air, of course, 
depends upon conditions, although seventeen 
parts of air to one of gasoline is considered an 
average proportion. The purpose of this quan¬ 
tity of air is to supply oxygen for combustion, 
and the quantity of oxygen supplied necessarily 
controls the number of parts of air to gasoline. 
Varying temperatures of the air mean varying 
quantities of oxygen, while the ratio of air to gas¬ 
oline is also dependent upon the quality of the 
gasoline. 

The correct proportioning of the air and the 
fuel is of great importance. If there is too 
much or too little gasoline within relatively nar¬ 
row limits the action of the engine becomes 
objectionable. This condition is found when the 
term lean or rich mixture is mentioned. 

It is possible to vaporize the liquid fuel in two 
ways—by heat and by vacuum. Vaporization of 
the liquid fuel by vacuum is only partly complete, 
for no matter how far the process of reduction 
goes, since the liquid which vaporizes does so by 
the abstraction of heat from the remainder, and 
this, of course, becomes colder until finally the 
temperature is so low that vaporization ceases 
until heat is again supplied from some other 
source. When vaporization is brought about by 
heat, the degree depends upon the amount of heat 

( 118 ) 


114 


Autocrajt 


supplied, since the liquid is constantly raised to 
or maintained at the proper degree. 

In actual practice neither of the above vapori¬ 
zation methods are carried to the limit, but both 
are applied together. Each of these vaporization 
actions help the other, namely, the air supplies 
heat to the liquid as it is cooled by vaporization 
under reduced pressure and due to pressure re¬ 
duction, helping the transfer of heat from the air 
to the liquid. 

All of the above is carried out in an instrument 
which is known as the carburetor. Gasoline is fed 
to the carburetor through a small pipe, which is 
commonly called the supply pipe, from the gaso¬ 
line or fuel tank, which may be located in sev¬ 
eral different positions. It may be located either 
in the cowl, under the front seat, or at the rear 
end of the chassis. From the tank the gasoline 
enters the carburetor through what is known as 
the float chamber, passing through a strainer and 
by a needle valve, which performs the functions 
of stopping the flow when a predetermined level 
is reached in the float chamber. This needle valve 
is governed by the action of the float, which rises 
as gasoline enters, these two units being con¬ 
nected by a suitable mechanism. 

The gasoline in the float chamber must be kept 
constant, so as to prevent it from flowing over 
the jet which, if permitted, will cause faulty run¬ 
ning of the engine. The action of this float is 
quite similar to a ball type of water trap, for as 
the ball rises it shuts off the flow of water, and as 
the float rises it brings the needle valve to its 
seat and shuts off the gasoline. These floats may 
either be made of cork or metal. The metal float 
must be made air-tight and hollow, so as to be 
sustained in the liquid. Cork floats are usually 
covered with shellac to prevent them from ab- 


Carburetor 115 

sorbing some of the liquid and becoming too 
heavy. 

The choke or strangling tube in the mixing 
chamber allows a current of air to pass by the jet 
which draws with it a proportion of gasoline 
spray, and as the gasoline and vapor reaches the 
intake manifold, it becomes a gaseous mixture, 
and enters the engine cylinders through the in¬ 
take valve on the downward stroke of the piston. 
Directly under the flange connecting the carbu¬ 
retor with the intake manifold is located a but¬ 
terfly valve, which controls the amount of gas 
entering the cylinders. Opening this valve per¬ 
mits the engine speed to increase, providing the 
mixture is proportioned properly. An increase 
in motor speed creates an increase in suction on 
the carburetor jet and increases the amount of 
gasoline issuing from the jet. This, of course, 
will give an Qverly rich mixture unless some 
means are provided for allowing more air. This 
is usually compensated for by an auxiliary air 
valve which is controlled by a spring, so that as 
the suction is increased more air is permitted to 
enter. 

There are a great many different carburetors 
used at the present time. Some of these control 
the proportions by raising the needle valve with 
increased engine speed, such as the Breeze and 
Schebler carburetors, while others control the 
air, such as the Kingston, K. D., Stromberg and 
others. Some carburetors also , work auto¬ 
matically. y. „ ,y.. 

In presenting this treatise it is quite difficult to 
describe every instrument made. However, an 
effort will be made to describe a number of the 
leading types which are classed as standard 
makes and used on quite a number of motor cars. 


116 


Auto craft 


Several illustrations are also included of carbu¬ 
retors, which are built by motor car builders to 
meet the peculiar requirements of their engines. 

THE HOLLEY CARBURETOR. 

Fig. 55 illustrates a sectional view of the model 
“H” Holley carburetor, which is provided with 
a free air opening and is so designed that the air 
is controlled by the suction of the engine. Before 
the fuel enters the float chamber it passes the 
strainer disc “A,” which removes all foreign mat¬ 
ter that might interfere with the seating of the 
special alloy-tipped float valve “B” under the 
action of the laminated cork float and its lever 
“C” 

Fuel passes from the float chamber “D” into 
the nozzle well “E” through a passage “F” 
drilled through the walls separating them. 
From the nozzle well the fuel enters the nozzle 
proper “G” through the hole “H,” knd rises past 
the needle valve “I” to a level in its cup-shaped 
upper end, which just submerges the lower end 
of the small tube “J,” which has its outlet at the 
edge of the butterfly valve. 

Cranking the engine with the throttle kept 
nearly closed causes a very energetic flow of air 
through the tube “J,” and its calibrated throttling 
plug “K.” But the lower end of this tube is 
submerged in fuel with the engine at rest. 
With the motor turning over under its own 
power, flow through the tube “J” takes place 
at a very high velocity, thus causing the fuel en¬ 
tering the tube with the air to be thoroughly 
atomized upon its exit from the small opening 
near the butterfly valve. This tube is called the 
“low speed tube” because for all starting and idle 
running all of the fuel and most of the air in the 
working mixture are taker through it. 


Carburetor 


117 


As the throttle opening is increased beyond 
that needed for idling of the motor, a consider¬ 
able volume of air is caused to move through the 
passage bounded by the conical walls “L” of the 



i. 


Fig. 55.—The Holley Model H Carburetor. 


so-called strangling tube. In its passage into the 
strangling tube the air is made to assume an an¬ 
nular, converging stream form, so that the point 
in its flow at which it attains its highest velocity 
is in the immediate neighborhood of the stand- 















118 


Autocraft 


pipe “M,” set on to the body of the nozzle piece 
“G.” The velocity of the air flow being highest 
at the upper or outlet end of the standpipe, the 
pressure of the air stream is lowest at the same 
point. For this reason there is a pressure differ¬ 
ence between the top and bottom openings of the 
standpipe “M.” thus causing air to flow through 
it from bottom to top. 

With very small throttle opening, the action 
through the standpipe (air passing downward 
through a series of openings “N” in the standpipe 
supporting bridge) keeps the nozzle cup thor¬ 
oughly cleaned out, the fuel passing directly from 
the needle opening into the standpipe. 

THE ZENITH CARBURETOR. 

In the Zenith carburetor, Fig. 56, the ratio of 
gasoline to air is kept almost constant during the 
entire range of motor speed by what is termed a 
compensating nozzle, which counteracts the mix¬ 
ture fed by the main nozzle. The main jet “G,” 
has another around it, “H,” which is fed by a 
well, “I,” which in turn is fed by the float cham¬ 
ber. Gasoline enters the strainer body “D,” 
passes through the wire gauge “D 1,” and enters 
the float chamber through the valve seat “S.” 
As soon as the gasoline reaches a predetermined 
height in the float chamber, the metal float, “F,” 
acting through the levers “B” and collar “G 2,” 
closes the needle valve, “G 1,” on its seat. From 
the float chamber to the motor gasoline flows 
through three different channels, in various 
quantities and proportions^ according to the speed 
of the engine and to the degree of throttle open¬ 
ing. With the throttle fully open, most of the 
gasoline flows through compensator “I,” then 
through plug “K” to the cap jet “H,” which sur¬ 
rounds the main jet. This main jet and cap jet 
work together and their combination furnishes 


Carburetor 


119 


the mixture, whatever be the speed of the engine. 
At low speed when the butterfly valve “T” is 
nearly closed, they give but little or no gasoline, 
but as there is considerable suction on the edge 



of the butterfly valve, the tube “J” terminating 
in a hole near the edge of the butterfly valve, 
picks up gasoline, which is measured out by a 
small hole at the top of the priming plug. The 
well over compensator “I” is open to the air 
through two holes, one of which is indicated be¬ 
low the priming plug on the illustration. 







































120 


Autocrajt 


THE MARVEL CARBURETOR. 

This instrument, Fig. 57, like most 11 other in¬ 
struments, consists essentially of a float chamber 
and a mixing chamber. Gasoline enters the float 
chamber and is filtered again before it reaches 
the needle valve and the low speed spray nozzle, 
when it stands at the same height as in the float 
chamber. All the air supplied to this instrument 
enters through one opening on the right marked 



“air inlet.” After it has passed the choker it 
divides, part of it going through the venturi tube, 
around the low speed spray nozzle, and the re¬ 
mainder passing above and opening the auxiliary 
air valve against its spring. Near the top and 
underneath the auxiliary air valve is located the 
secondary or high speed spray nozzle. 

The speed of the motor and the condition ol 
the throttle directly effect the proportioning of 






































































Carburetor 


121 


the incoming air, as it passes through each of 
these courses. At low speed and nearly closed 
throttle the suction of the motor is very light, so 
that practically all of the air passes through the 
venturi tube. As the speed and suction of the 
motor increases with the throttle opening the 
auxiliary air valve is lifted from its seat and a 
larger proportion of air enters the intake mani¬ 
fold through this passage. 



Fig. 58.—The Stromberg Carburetor. 


The rush of air through the venturi tube picks 
up and vaporizes gasoline from the low speed 
spray nozzle and carries it past the throttle and 
through the intake manifold to the cylinders. 
When the suction at the auxiliary air valve has 
increased sufficiently to create a high velocity at 
this point, ‘gasoline is also picked up from the 
high speed spray nozzle and carried into the cyl- 
. inders in the same manner. 































122 


Autocraft 


THE STROMBERG CARBURETOR. 

The Stromberg carburetor, shown in Fig. 58, 
also has two adjustments, a high and a low speed, 
both working directly in the gasoline supply, that 
is, the low speed adjustment is by the needle 
valve and the high speed by the air valve. The 
gasoline for low speed is taken from the spray 
nozzle, located in the venturi, through which the 
heated air passes. There is also a second nozzle 



CONSTANT AIR 
"S-OPENINGy" 


UPPER AUTOMATIC 
AIR valve r ' 


ME T ERING1 
PIN NOZZLE 


DASH POT 
PISTON / 


[lower air valve 


GASOLINE 

intake , 


r S&RAYT 

nozzle] 


Fig. 59.—The Rayfield Carburetor. 

in the center of the air valve, which is auto¬ 
matically regulated by the opening of the air 
valve, thus supplying the necessary volume of 
gasoline for high speed. This air valve termi¬ 
nates in a dash pot, which eliminates all flutter¬ 
ing, as it is submerged in a puddle of gasoline 
supplied from the float chamber. This carburetor 
has a somewhat different float mechanism than 
those depicted above, in that the float valve 
passes through the float, which is metal. 

THE RAYFIELD CARBURETOR. 

This instrument, Fig. 59, is of the dash pot 
type. The fuel in this type is taken in above 


























Carburetor 


123 


the piston and is fed to the metering pin nozzle 
from below the piston. From the illustration it 
will be noted that the floating piston or dash pot 
has a crank valve. This valve causes slow open¬ 
ing and quick closing of the air valve. Air is 
supplied through three openings, constant air 
opening, lower air opening and upper automatic 
air valve. Gasoline is supplied through a main 
nozzle and the auxiliary metering pin nozzle. At 
low motor speed two air openings are closed and 
all the air is taken in through the constant air 
opening. The automatic air valve controls both 
of the auxiliary air openings and is directly con¬ 
nected to the dash pot. This dash pot operates 
in a puddle of gasoline, which is maintained con¬ 
stantly through a passage from the float chamber. 
Gasoline is drawn from this dash pot to the 
metering pin nozzle. The dash pot performs 
three purposes. It prevents the air valve from 
fluttering during accelerations, it retards the 
opening of the air valve for a few seconds when 
the throttle is opened, giving a quick pick up. 
When the upper automatic air valve starts to 
open it pushes the dash pot piston down, forcing 
the gasoline up through the metering pin nozzle, 
spraying it out into the mixing chamber, when 
the air and gasoline become mixed to an ex¬ 
plosive mixture. 


The Magneto 

In order to get a good understanding of the 
method of producing electricity by magnetos, it 
is necessary to review some of the fundamental 
steps in the way of the most important dis¬ 
coveries. 

Even in the times when little was known about 
electricity, a certain relation was discovered be¬ 
tween electricity and magnetism, and by the ex¬ 
periments of Faraday, Ampere, Davy and Oersted 
it was discovered that whenever a current of elec¬ 
tricity is passed through a conductor there are 
magnetic lines of force around the conductor ex¬ 
actly the same as the lines of force between the 
poles of a magnet. The space around the con¬ 
ductor which is influenced by this force is called 
the “magnetic field.” 

By placing a magnetic needle near a wire 
through which an electric current is passed it will 
be noticed that the needle is deflected, tending to 
point perpendicularly toward the wire. In 1831 
Faraday published his discovery of the corollary 
principle that passing a conductor through a mag¬ 
netic field so that the conductor cuts through the 
lines of force, causes an electrical pressure to be 
induced in the conductor, the direction of the 
flow of current bearing a fixed relation to the direc¬ 
tion in which the conductor is moved in the field. 
The rule governing these relations can easily be 
remembered by studying the illustration of the 
hand. Fig. 61 will illustrate how the direction of 
the current changes every time the armature 
moves 180 degrees through the field, producing 
what is known as an alternating current. 

The part which is moved through the field is 
called the “armature” and in a magneto the core 

(124) 


Magneto 


125 


of the armature is in the form of an “I.” In a 
high tension magneto there is wound around the 
core first one coil of wire, which is called the 
“primary coil,” consisting of a comparatively few 
turns of heavy wire, and on the outside of the 
primary winding is the secondary winding, con¬ 
sisting of a great many turns of fine wire. 



Fig. 60.—The hand rule for determining direction of induced 

current. 


\ 

In a low-tension magneto this secondary wind¬ 
ing takes the form of a coil which is located out¬ 
side of the magneto. Without the secondary 
winding only a current of low voltage can be ob¬ 
tained, and since a high voltage is required to 
make the current jump the gap in the spark plugs, 
a secondary winding in some form is necessary. 
The greater simplicity of the high-tension magneto 
in this respect is obvious, and in addition to the 
simplicity, the spark produced by the high-tension 
magneto is superior for ignition purposes on ac¬ 
count of diminished loss of current by resistance 
in the wires. 

Experiments have led to the discovery that by 
passing a current through a coil of wire around 





126 


Autocrajt 


which a second coil is wound, a current of high 
voltage is induced in the outside coil at the 
moment the primary current is broken. So the 
necessity of a device which will break the pri¬ 
mary current when a spark is desired in the 
secondary coil is apparent. This device is called 
the “breaker.” 




Fig. 61.—Coil revolved in magnetic field. 


/ The Circuit Breaker. 

This circuit breaker generally consists of 
stationary and movable contact points which are 
ordinarily kept in contact by a spring. The 
breaking effect is usually accomplished by a 
cam which suddenly separated the contact points. 

'When these two contacts are suddenly sepa¬ 
rated there is a tendency for the current to 
continue to flow across the gap. This results 
in a hot spark being formed, which will not only 
burn the points away, but will also prevent a 
rapid cessation of the current. 

The Condenser. 

To avoid this a condenser is built into the 
magneto, which consists of two sets of tin-foil 

















Magneto 


127 


sheets, sheets of opposite sets alternating with 
each other and separated by insulating material. 
One set is grounded, while the other is con¬ 
nected with the primary winding. These con¬ 
densers are capable of absorbing an electrical 
charge. 

The Safety Gap. 

The electromotive force of the secondary 
winding is always limited to the size of the 'gap 
in the spark plug; however, should the plug gap 
be too large for the sparks to pass, this force 
might build up to such a point as to puncture 
the insulation of the windings. A safety gap 
which is larger than that of the plugs is usually 
provided, which will permit a discharge and 
prevent the electromotive force from rising 
still higher. 

The Switch. 

The switch serves the function of cutting 
out the circuit breaker, and the priming winding 
is short circuited all the time, so that the open¬ 
ing and closing of the contact points has no 
effect. 

Magneto Types. 

There are two types of magnetos as men¬ 
tioned above—one in which the secondary wind¬ 
ing is placed on the armature, and the other in 
which this is placed in coil located outside of 
the magneto. Both, however, are termed high- 
tension units, and furnish a jump spark. 

Classification. 

This may be divided into two groups, accord¬ 
ing to the principle employed to generate the 
initial impulses in the magnetic field. These are 
generally termed the armature and conductor 
type. In the former electrical current is gener¬ 
ated by revolving the armature and its windings 
between the pole pieces or shoes. The inductor 


128 


Autocraft 



type consists of two fan-shaped inductor wings, 
which are mounted on a shaft and rotated within 
a stationary winding in the magnetic field. 

The Simms Magneto. 

The armature of this magneto is of the true 
high-tension type, on which is wound both the 
low-tension primary and the high-tension second¬ 
ary windings, connected in series. This instru¬ 
ment creates a high-tension current directly in 


Fig. 62.—The Simms High Tension Magneto, showing 
Interrupter and Distributor. 

the armature, and does not use any exterior coil 
or other device to step up or transform the cur¬ 
rent, as the instrument is a complete unit within 
itself. 

The armature windings are heavily impreg¬ 
nated with an insulating substance of high di¬ 
electric strength, which thoroughly protects the 
armature against water, moisture or short cir- 




Magneto 


129 


cuits. This armature is mounted on high-grade 
annular ball-bearings, the idea being to eliminate 
friction and all difficulty due to insufficient 
lubrication. 

The contact breaker interrupter cam ring 
is a one-piece, hardened and ground, which 
insures perfect synchronism at all speeds, and is 
accurate at all positions from full retard to full 



Fig. 63.—Extended Pole Shoe of the Simms Magneto. 

advance. The platinum points are made excep¬ 
tionally large, to provide long life. The contact 
breaker is made quite accessible, and can easily 
be removed for cleaning. 

The distributor is located above the armature, 
being driven by gears. It is both dust and water 
proof, and made from a hard rubber substance 
which is claimed to be decidedly superior 
to any composition material. The distributor 
brush is made extra large, and the brass seg- 















130 


Autocrajt 


ments have an exceptionally wide surface, in 
order to reduce wear to a minimum. The dis¬ 
tributor terminals are of the screw type, and 
located on the face of the distributor for securely 
fastening the terminals. This unit is so ar¬ 
ranged that it can easily be removed for cleaning. 



Fig. 64.—Sectional View of the Heinze High Tension Magneto 
equipped with Magnets of Circular Section. 


A safety gap is also provided to prevent 
damage to the magneto, in the event of one or 
more high-tension cables becoming disconnected 
from the spark plugs. The gap is so located that 
its action may be readily observed for the pur¬ 
pose of locating trouble in misfiring. 

One of the principle features of this magneto 
is the new form of extended pole shoe, which 
enables the magneto to produce a spark of un¬ 
usual intensity at full retard or low speed. It 
is claimed that this feature was a disadvantage 
formally in starting on the magneto direct, and 
was facilitated by advancing the spark as far as 
was safe when cranking. 











































































Magneto 131 

The Heinze Magneto. 

Most all magnetos employ magnets of the 
horseshoe type, which are usually rectangular. 
However, in the Heinze magneto these are of 
round section, as illustrated. The pole pieces 
and the armature are also of the round type. 


Fig. ^5 .—Method of setting Carbon Brushes in relation to the 
segments on the Bosch N U 4 Magneto. 

The round type armature permits the minimum 
amount of wire in both the primary and second¬ 
ary windings which cuts down the resistance, 
and, therefore, it is claimed gives a hotter spark. 
These round armature windings are assembled 
about a round iron core made up of a bundle 
of very small and correspondingly well-annealed 
soft iron wires. An arrangement for varying 








132 


Autocrajt 


the timing is fitted as in most all other types. 
The armature shaft is mounted on ball-bearings, 
while the contact breaker and distributor are 
mounted at the rear of the instrument. 

The Bosch High-Tension Magneto. 

The Bosch Company makes a number of high- 
tension instruments. However, the Model N. U. 
4 will be described here, since it possesses several 



Fig. 66.—New Bosch Type N U 4 Magneto. 

features which are not incorporated in the other 
types. 

Like all other Bosch instruments, the arma¬ 
ture carries the primary and secondary windings, 
which are in two portions, the primary consist- 
ting of a few layers of comparatively heavy 
wire, and the secondary consisting of many 
layers of fine wire. This primary winding has 
one end connected to the armature core, and the 
other end to the insulated contact block support¬ 
ing the long platinum pointed screw on the 








Magneto 


133 


magneto breaker or interrupter. The interrupter 
lever, carrying a short platinum pointed screw, 
is mounted on the interrupter disc, which, in 
turn, is electrically connected to the armature 
core. The primary circuit, therefore, is com¬ 
plete whenever the two platinum points are in 
contact, and broken whenever the points are 
separated; and as high-tension current is gen¬ 
erated only at each separation of These points, the 
importance of this breaker or interrupter is 
evident. 

In the usual form of Bosch instruments, the 
secondary winding producing the sparking cur¬ 
rent is practically a continuation of the primary, 
its inner end connecting with the latter, and the 
other end leading to an insulated slip ring 
mounted on the driving shaft end and rotating 
with the armature. From the slip ring the high- 
tension current is collected by a brush and passed 
to the distributor. 

In Model N. U. 4 there is absolutely no con¬ 
nection between the primary and secondary 
windings. These, in fact, are entirely insulated 
from each other, and the two ends of the second¬ 
ary connected to two metal segments in a double 
slip ring attached to and rotated with the arma¬ 
ture shaft. As the armature rotates the two 
slip-ring segments pass the current to four 
brushes, each of which is connected by its re¬ 
spective cable to a spark plug in the cylinders. 
The distribution of the high-tension current is 
thus effected without resource to the usual 
separate distributor. 

The Mea Magneto. 

The distinct innovation and improvement in¬ 
corporated in the Mea magneto consists in the 
bell-shaped magnet here illustrated, which is 
mounted horizontally and in the axis with the 
armature, instead of the customary horseshoe 


134 


Auto craft 


magnets placed at right angles to the armature. 

This makes possible and practical the simul¬ 
taneous advance and retard of the magnets and 
breaker instead of the advance and retard of the 
breaker alone* 

An additional feature of the bell-shaped 
magnet is its magnetic permanency. The life of 
a magnet is the greater the smaller its stray field. 

From the diagram of the Mea magneto shown, 
the breaker can be seen at the end of the magneto 



* Fig. 67.—Bell-Shaped Magnet of the Mea Magneto. 


opposite the shaft, and it will be seen that the 
fibre roller (31), which is actuated by a cam (40), 
presses the spring (30), carrying with it the 
platinum point (34), so that the primary current 
is interrupted between the two platinum points 
(34 and 33). At the moment when this current 
is interrupted a spark of sufficient intensity to 
burn off the ends of the platinum points would be 
produced if a condenser were not introduced. 
This is indicated by 12 and consists of layers of 
foil insulated from each other with paper, or mica. 

As before stated, when the primary current is 
interrupted a high-tension current is produced in 














Magneto 


135 


the secondary coil, which is directly connected to 
the slip ring (4), and in turn is delivered to the 
high-tension carbon (77). This carbon is pressed 
against the slip ring by means of a light spring 
and the current passes through the carbon and 
into the knob terminal on top of the high-tension 
carbon holder. From thence it travels across the 
high-tension bridge (84) and down into the center 



Fig. 68.—Cross-Section of BH Type Mea Magneto. 

(“Section through magnets in lower half of magnets is taken at 
right angle to rest in order to show pole piece construction.”) 


terminal of the distributor body and into the col¬ 
lecting carbon (69). This carbon is connected 
metallically with the distributing carbons (68), 
• which, as they rotate inside of the distributor 
body, deliver the high-tension current to the brass 
segments and up into the cables, which in turn 
carry the current to the spark plugs. The interna) 
electrode of the spark plugs is insulated and the 
current jumps from the point of this electrode 
to ground in the part of the spark plug which is 
in contact with the cylinders. This is the spark 
which ignites the gas. 



























136 


Autocrajt 


Provision is made for grounding the spark in 
case there is a broken or improper connection to 
ground through the spark plugs. The spring 
leading from the terminal of the high tension 
carbon holder connects with a brass pin that is 
set in the center of a mushroom shaped piece of 
porcelain. This pin is entirely insulated from 
ground by only a small gap. When the electric 
pressure in the armature is raised above normal 
by a break in the natural course of the secondary 
current, the electricity will jump the gap above 
referred to and go to ground in the magneto hous¬ 
ing. In this way the armature is saved from 
destruction in case of a broken connection to the 
spark plugs. 

As it is necessary, in order to obtain the highest 
efficiency in a gas engine, to time the spark so 
that it will always occur when the piston is at 
the highest point of its stroke, magnetos have been 
so constructed that the breaking of the primary 
spark c-an be controlled within a certain range. 
This is accomplished by turning the cam which 
actuates the breaker forward or backward, so that 
the break will occur later or earlier, respectively. 
As it takes an appreciable amount of time for the 
gas in the cylinder to ignite, it is necessary to light 
the gas earlier as the speed of the motor increases. 

There are also a number of other high-tension 
magnetos of the armature type. However, they 
have been omitted, owing to the limited space. 

The Inductor Type Magneto. 

The instruments described above were said 
to generate their current on the principle of 
placing the windings on the armature core. 
However, the inductor type differs from these 
in that the windings are stationary and the ar¬ 
mature is replaced by inductors which revolve. 
The inductor type, like the armature type, con- 


Magneto 


137 


sists of horse-shoe shaped magnets and pole 
shoes, which form the magnetic field mounted 
upon a non-metallic base. The inductors are 
placed upon a shaft, which is termed the rotor 
shaft, while the inductors in some cases are fan¬ 
shaped. 

The contact breaker or interrupter is also used 
to open and close the primary circuit at the 



Fig. 69.—The Dixie Inductor Type High Tension Magneto. 

proper time, while the distributor is also resorted 
to to distribute the high tension current to the 
proper cylinders. In fact, this type of instrument 
incorporates all of the principal parts mentioned 
in connection with the previous types, such as 
the condenser, safety spark gap and switch. The 
windings may be arranged for either high or low 
tension current and may either be placed in the 
magnetic field, at the rear of the magneto, or the 
secondary winding may be incorporated in a coil. 

The Pittsfield Inductor Type Magneto. 

The Pittsfield magneto employs the induction 





138 


Autocrajt 


method of generating current and may be classed 
as a high tension instrument. While the usual 
primary and secondary winding are utilized, they 
are not incorporated with the armature, but are 
at the rear of the instrument and stationary. 
This instrument also has four pole shoes instead 
of two. Two of these are attached to the per¬ 
manent magnets in the usual manner. The oth¬ 
ers, with the iron core of the coil, comprise the 
magnetic field in which the inductor rotates on 
ball bearings. m 

One end of the primary winding of the trans¬ 
former coil is connected to a contact button which 
is at the left of the horizontal bar above the 
interrupter mechanism. The other end of the 
primary i-s attached to a contact plate incorpo¬ 
rated in the horizontal bar referred to, which 
is secured onto the field and insulated. A con¬ 
nection is made for the passage of current to the 
platinum contact piece and contact screw. This 
contact breaker or interrupter consists of a cam 
which separates the point twice during each revo¬ 
lution, through a lever bearing on a cam and carry¬ 
ing one of the points. The distributor is of con¬ 
ventional design and mounted above the inductor 
or rotor shaft. 

The secondary winding is incorporated in a 
transformer coil mounted at the rear end of the 
magneto. One end of the secondary winding is 
connected with one end of the primary, while the 
other is attached to a metal bridge which connects 
with the safety spark gap. From this bridge the 
high tension current is conducted to the distribut¬ 
ing brush, by conductors which are insulated. 

The Dixie Magneto. 

This is another instrument of the inductor 
type which has been introduced by the Splitdorf 
Co., especially for eight and twelve cylinder en- 


Magneto 


139 


gines, which, it is claimed, has solved the igni¬ 
tion problem of these V-type engines. This in¬ 
strument also generates a high tension current 
without the use of an outside coil. 

Its most radical departure from ordinary mag¬ 
neto practice consists in having the field mag¬ 
neto straddling the length of the revolving part, 
or rotor, so that the axis of this rotor lies in the 
central plane of the field magneto, instead of 
being perpendicular thereto as in the ordinary 
construction. No movable wires are used, as the 
windings are stationary, the current being in¬ 
ducted by the rotary movement of the rotor, 
which consists of a central part of non-magnetic 
material with pole extensions of magnetic ma¬ 
terial on each end, the whole unit being supported 
on ball bearings. 

The distributor is of the so-called compound 
type, as in the eight cylinder type there are two 
rows of four segments each and in the twelve 
cylinder type there are two rows of six segments 
each. These segments are arranged on cylin¬ 
drical surface instead of a flat surface. Two 
radial contact brushes are carried by the re¬ 
volving member of the distributor, each being 
adapted to make contact with one set of segments. 

The contact points of the interrupter are 
opened by a cam mounted on the rotor shaft, as 
the contact points are stationary and may be ad¬ 
justed while the instrument is running. 

The Remy Model “R-D” Inductor Type 

Magneto. 

This instrument was formerly made by the 
Remy Co., and while it is of the inductor type, 
it is designed to generate a low tension current, 
which is transformed to a high tension through 
a transformer coil. The accompanying illustra¬ 
tion shows the rotor shaft which has fan-shaped 


140 


Autocrajt 



inductor wings, and the stationary winding lo¬ 
cated between the two inductor wings. This 
rotor shaft is mounted on ball bearings and the 
rear end carries the distributor driving gear and 
the contact breaker. The distributor is mounted 


Fig. 70.—Cut-Away Section of the Remy Model “R D” Low 
Tension Inductor Type Magneto. 

above the rotor shaft and is of conventional de¬ 
sign. Various types of coils have been used with 
this instrument. 

There are a number of magnetos of the three 
types mentioned above made in this country, but 
owing to the space required to describe each one 
it has been necessary to omit quite a few. How¬ 
ever, the above descriptions serve to cover all 
types excepting details of design. 








The Front Axle 

T HE front axle of a motor car is largely de¬ 
pended upon for safe control of the ve¬ 
hicle, since this must carry the forward 
portion of the load and must be arranged as to 
permit steering the front wheels. This is ac- 
cbmplished by pivoting the front wheel spindles 
and holding them in proper relation to each 
other by a tie rod. These spindles are pivoted 
from the axle proper and are generally termed 
steering knuckles. The spindle and its pivot are 
forged integral, while the levers for steering 
connections may also be forged integral or keyed 
in position. 

Various Types. 

Steering knuckles at present are of three dif¬ 
ferent types, which are known as the Elliott, 
reversed Elliott and Lemoine types. American 
practice is divided, however. The first two are 
more extensively used than the latter. In the 
Elliott type the steering knuckle is T-shaped and 
the axle proper has two forked ends which fit 
over the knuckle. A long bolt, termed the king 
bolt, passes through both. In the reversed type 
the knuckle is forked and the axle ends have a 
T, while in the Lemoine type both axle end and 
knuckle form L’s. In practice the construction 
of each type differs somewhat, depending some¬ 
what upon the type of bearing and the method 
of mounting the knuckle in the axle end. 

Owing to the importance of the knuckles and 
their levers, these are always forged from a 
good quality of steel and heat treated. Location 
of the tie rod depends upon the general arrange¬ 
ment and may either be placed in front or in the 
rear of the axle proper. 

(141) 


142 


Autocrajt 


The Axle. 

Material for the axle proper is generally 
forged from medium carbon steel, and may 
either be of solid rectangular or I-beam section. 
The latter section, however, is almost universally 
used. Some few manufacturers use tubular 
axles, with drop forged ,axle ends secured to 
them. 

Front Axle and Frame Connections. 

In conventional designs, the only attachment 
between the axle and the frame is the vehicle 
springs, which are of the cantilever, semi-ellip¬ 
tic, quarter-elliptic or full elliptic type. These 
springs are made up from a number of steel 
plates. The upper plate usually has an eye at 
each end which is connected to the frame, while 
the mass of leaves are clipped to the axle at ap¬ 
proximately the center of the spring. This ap¬ 
plies to the semi-elliptic type. However, in the 
full elliptic one-half is clipped to the axle and 
the other to the frame at approximately their 
centers. In the quarter-elliptic type, the forward 
end of the spring is fastened to the axle, while 
the rear end is fastened to the frame. These 
spring chips are of the box type and fit snugly 
over the spring leaves, which rest on a pad on 
the axle proper and the ends of the clips pass 
through holes in this pad and are retained by 
nuts. 

I-Beam Axles with Elliott Type Knuckles 

Fig. 71 illustrates the 1915 Marmon Six axle, 
having a drop forged I-beam center with integral 
spring pads, the topmost surface of this pad being 
considerably below the center of the wheel. The 
knuckle is of the Elliott type and is drop forged 
with an integral spindle, “H,” on which the wheel 
rotates. A large Timken bearing is mounted in 


Front Axle 


143 


the upper end of the axle fork, which is adjust^ 
able, since it is mounted on the king bolt, “C,” 
which in turn is retained by nut “B.” The entire 
thrust load is carried by this bearing, as a spacer 
is used at the lower end, which holds the king 
bolt central. In order to properly mount the 


Fig. 71.—Marmon 41" Front Axle with Elliott Type Steering 

Knuckle. 



bearing it is necessary to have the knuckles and 
king bolt work in unison. This is accomplished 
by the stud “A,” which acts as a key. The drag 
link from the steering gear is connected to the 
ball “K,” which is mounted in the knuckle lever. 
This lever has a projection to which the drag link 
is attached. The knuckle has a base near its 
lower end into which the lever is keyed and re¬ 
tained by a nut. 

The wheels are mounted on Timken bearings 
“D” and “E” and are retained by a washer “J” 
and a nut. The hub cap, which is not shown, 
encloses the center bearing “D,” while the inner 
one is enclosed by a steel stamping attached to 






















































144 


Autocraft 


the hub by means of screws “G.” In order to 
prevent grease from working out at this end and 
grit from entering, a felt washer “F” is placed in 
this stamping or shield. 

Fig. 72 depicts the Reo axle, which has Elliott 
type knuckles and a drop forged center. The 
knuckle and spindle are also forged integral. 
However, they carry bronze bushings for sup¬ 
porting the king bolt, while a taper on the king 
bolt and a hardened steel washer take the thrust. 



The wheels are mounted on roller bearings 
within a cast hub, while the hub flange is made of 
pressed steel. A ball is forged integral with the 
knuckle lever, while the general construction and 
mounting of the tie rod end and bolt is similar 
to the king bolt. Grease cups are provided in 
both so that the lubricant can be forced directly 
to the bearings. 

The Reversed Elliott Type. 

Fig. 73 illustrates the reversed Elliott type of 
knuckle, which is quite popular on foreign cars 
and rapidly gaining favor in this country. The 
bearings are always placed in the knuckle fork 
and are provided with hardened steel bushings. 





























Front Axle 


145 


A ball thrust bearing may be fitted as shown. 
However, hardened steel thrust washers may 
also be used. Steering levers and the other de¬ 
tails may be mounted as described above. 

The Lemoine Type. 


The Lemoine type of knuckle is shown in Fig. 
74. The type was at one time very popular on 
French cars. However, it was abandoned as 



Fig. 73.—Reversed Elliott Type Knuckle. 


the thrust load on the bearings is very large, 
even when the vehicle is at rest or running over 
a smooth road surface. This load is considerably 
increased by shocks on uneven pavement. The 
axle end in this case is formed into a nearly ver¬ 
tical hub of considerable length, and through 
this is a nearly vertical hole. The king bolt 
passes through the knuckle and the hub on the 
axle end and is secured by a nut in order to pre¬ 
vent the knuckle from' dropping. A thrust bear 
ing must be used between the axle and the 
knuckle, and so arranged that the entire load can 
be taken on it. 










































146 


Autocraft 



The Inverted Lemoine Type. 

A modification of the Lemoine type is shown 
in Fig. 75, which may be termed inverted Le¬ 
moine type. In this construction the axle also 
has a hub with a nearly vertical hole. However, 
the knuckle has the king bolt or pivot pin forged 



Fig. 75.—Overland Axle with Inverted Type Lemoine Knuckles. 













































Front Axle 


147 


integral, and the wheel spindle is located above 
the axle end instead of below. The wheels are 
' mounted on taper roller bearings, while the 
knuckle is mounted on hardened steel washers 
and bushings. The steering levers are keyed 
directly to the end, the pivot and all are retained 
by a large castellated nut. This illustration rep¬ 
resents the 1917 Overland front axle. 

Wheel Bearings. 

All American motor cars are equipped with 
anti-friction bearings for wheel mounting, such 
as the ball and roller types, which are capable 
of carrying both a radical and thrust load. The 
mounting of these bearings presents no difficulty, 
and they are generally provided with adjustment 
for wear. These bearings must be thoroughly 
enclosed so that the hubs can be packed with 
grease and kept free from grit. Should the pres¬ 
ence of grit be detected, the only thing to do is 
to wash the bearings thoroughly with gasoline 
and dry them, after which the lubricating must 
be done over again. It is good practice to ex¬ 
amine the wheel bearings every 4,000 miles, or 
at least once a year, and while they are being ex¬ 
amined they should be thoroughly cleaned. Cup 
grease should be used for lubricating them. 

Wheel Alignment. 

An important factor which has an intimate re¬ 
lation to the mileage obtained from tires is the 
alignment of the wheels. This is especially true 
of the front wheels, which should be tested at 
regular intervals. This can readily be accom¬ 
plished by measuring the distance between the 
inside of the rims at front and rear of axle. 
The same distance from the floor. They can 
easily be adjusted by the tie rod, which always 
has an adjustment for this purpose. 


148 


Autocrajt 


The steering knuckles are usually placed at a 
slight angle to make steering easier. This means 
that the front wheels should toe in about ^4-inch, 
which is generally enough to correct the ten¬ 
dency of the front wheels to toe outward when 
the car is running. 

Wheels. 

Wheels occasionally develop a squeak, which 
in the majority of cases is due to loose hubs. 
This can easily be remedied by tightening the 
hub bolts. However, should the squeak occur in 
the felloe or spokes, it is due to the wood drying 
out, as it may have been in a green state when 
cut. About the only remedy for this is to thor¬ 
oughly soak them in water, which causes the 
wood to expand, thus tightening the joints. 
Wheels may also be tested for trueness by jack¬ 
ing up one at a time and placing a stationary 
point almost against the felloe band, then re¬ 
volve the wheel to determine if the distance be¬ 
tween the stationary point and the felloe is the 
same at all points on the circumference. 


The Clutch 


I T IS a rather difficult matter to compare the 
advantages and disadvantages of the automo¬ 
bile clutch, owing to the variety of types, how¬ 
ever, the requirements of a good clutch may be 
itemized as follows: 

It must possess ample holding power and re¬ 
liability to transmit power given it. It shall 
be capable of a gently progressive engagement, 
without undue care on the part of the operator, 
and its engagement shall be prompt and complete. 

Owing to the defects of motor car engines, 
relative to their flexibility, it is the inability to 
develop their full torque from a standstill. The 
crankshaft must rotate at speeds consistent with 
power requirements, while the road wheels neces¬ 
sarily must rotate consistent with road condi¬ 
tions, or at the will of the operator. This defect 
makes it necessary to use \ transmission, which 
with its various speeds increases the motor 
torque. The engine is started by an electrical 
starting device, which produces just enough 
torque to spin the engine and overcome the re¬ 
sistance on the compression stroke. This, of 
course, means that it is necessary to disconnect 
the engine from the other driving units of the 
vehicle. Wheri the engine has attained its speed 
it must be connected with the driving units of 
the vehicle again. 

From the above it can readily be understood 
that the device used for this purpose must per¬ 
mit a certain amount of slippage until the motor 
speed has been reduced, and the speed of the 
vehicle gradually accelerated until the two cor¬ 
respond, thus preventing shock and jar to the 
driving mechanism. 


( 149 ) 


150 


Autocraft 


The device used to accomplish these features 
is called the clutch, its location most generally 
being in close proximity to the motor, the most 
popular position being inside the engine fly¬ 
wheel ; however, motor cars have been built in 
which the clutch was mounted in a separate 
compartment at the front end of the transmis¬ 
sion. A single clutch is invariably employed to 
connect and disconnect the engine from the driv¬ 
ing units through the different gear reductions. 
These clutches are nominally held in engagement 
by springs and are controlled by a foot pedal, 
which serves to release the friction members 
when it is necessary to disconnect. 

There are quite a variety of clutches in use 
at present; however, they are all of the friction 
type, and are either cone or multiple disc types. 

The Cone Clutch. 

The cone clutch consists of a conical-shaped 
member which engages with a female conical 
opening in the flywheel, and a spring to hold it in 
engagement. It may either be operated dry or 
in oil; however, for the former it must be faced 
with a material which will not char or burn 
during slippage. When operating in oil the sur¬ 
faces are usually metal to metal. The direct 
type in which the male member travels from the 
flywheel in disengaging is universally used at 
present. The action of the members of a cone 
clutch is similar to a wedge movement. Con¬ 
structions vary and in practice both aluminum 
and pressed steel male members are used. The 
friction material is either leather or some type 
of brake lining, such as raybestos, multibestos, 
non-burn, etc. The most usual method of mount¬ 
ing is on an extension of the crankshaft with a 
suitable bearing and a ball thrust bearing to take 
the thrust of the spring. In some cases cork 


Clutch 


151 


inserts are used to obtain a higher coefficient of 
friction, while small flat springs are placed under 
the facing to insure gradual engagement. 

The Disc or Plate Clutch. 

The disc clutch consists of a number of discs 
or plates which present a multiplicity of small 
surfaces in preference to the two large surfaces 
of a cone clutch. The discs are divided into two 
sets, one being termed the driving discs and the 
other the driven discs. The driving set of discs 
are provided with key slots or holes on their 
outer circumference, which fit over hardened 
steel keys or studs fastened to a plate which car¬ 
ries the housing, or to the fly-wheel if the clutch 
is to operate dry. The driven discs are also 
provided with slots or holes, but these are 
placed on the inner circumference and fit over 
keys or studs attached to a hub or flange mounted 
on the transmission shaft. It is general practice 
to use one more driving discs than there are 
driven discs, so that the two end discs may be of 
the same kind. The driving set is driven by the 
engine, while the remaining set is attached to 
the transmission shaft. 

When these clutches are intended to operate 
in oil they generally consist of a large number 
of plates, usually steel and bronze, forming a 
metal to metal contact. These clutches may also 
be operated dry, but the driven discs must be 
faced with a friction material as that used for 
cone clutches; however, the number of discs may 
be decreased. For this discs of both sets are 
■usually made of saw-blade steel. 

There is another type of disc clutch which 
operates dry and is sometimes called a plate 
clutch. In this type the plates or discs are made 
much larger in diameter and but three or five 
are used. The driving members are either faced 


152 


Autocraft 


with friction material or of bronze and provided 
with cork inserts, while the driven members are 
made of steel. 

The Cone Type. 

Fig. 76 illustrates the Marmon cone clutch, 
which is of the direct type. The cone or male 
member is made of aluminum, provided with a 
friction facing, and is bolted to a steel housing 
mounted on the extension of the crankshaft 



Fig. 76.—Marmon Cone Clutch with Aluminum Cone. 


surrounding the clutch spring. This spring is 
provided with an adjustment and a thrust bear¬ 
ing which are enclosed in the housing. This 
housing carries an extension for mounting the 
hub of the universal joint and also a large ball 
thrust bearing to take the thrust in disengaging 
the clutch. Cone clutches are generally designed 
so that the spring thrust is self-contained. In 
this illustration one large spring is shown; how¬ 
ever, in some cases several small springs are used. 










































































Clutch 


153 


These are generally fastened to a spider mounted 
in back of the cone. 

The Multiple Disc Type. 

A multiple disc clutch which has been exten¬ 
sively used in this country and abroad is the 
Helle-Shaw clutch shown in Fig. 77. The discs 
are made of steel and bronze, with V-groove 
corrugations. Only the walls of these grooves 
come in contact and the remaining portions of 
the discs serve to radiate the heat engendered 
during slippage. To permit the oil to enter and 



Fig. 77.—Hele-Shaw Multiple Disc Clutch, with Grooved Plates. 

escape freely, these discs have small holes in 
the inner walls of the grooves near the peak. 
The action obtained by these grooves is a wedge 
action similar to the cone clutch. In this clutch 
pressed steel is used wherever possible to reduce 
weight. It is termed a universal type, as a uni¬ 
versal joint is mounted inside of the clutch. An 
adjustable clutch brake is mounted upon the 
drive shaft. As oil is used, the plates must be 
enclosed, and this is the purpose of the pressed 
steel housing. The clutch is mounted by bolt¬ 
ing it to the fly-wheel. 




























































































154 


Autocrajt 


The Multiple Dry Disc Type. 

Fig. 78 illustrates The Reo Six dry disc clutch, 
which is quite simple in construction. The driv¬ 
ing member is cast integral with the fly wheel 
and has a number of gear teeth cut on its inner 
circumference which mesh with teeth cut in the 
driving plates. The driven member is supported 



Fig. 78.—Reo Multiple Dry Disc Type Clutch. 


by a Hyatt roller bearing mounted on a butt bolted 
to the fly wheel. This member has teeth cut on 
its outer circumference which mesh with teeth 
cut on the inner circumference of the driven 
plates. Both sides of the driving plates are faced 
with raybestos, and small springs, adjustable from 
the inner side of the flywheel, holds both sets of 
plates in position. 
































































Clutch 


155 



Fig. 79.—Borg & Beck Dry Plate Clutch. 





























































































































156 


Autocrajt 


The Dry Plate Type. 

Fig. 79 illustrates the Borg & Beck dry plate 
clutch which is used on a number of vehicles of 
both passenger and commercial types. This con¬ 
sists of a driven number keyed to the transmis¬ 
sion shaft and two raybestos discs which bear 
against the fly wheel and the driving member 
keyed to the fly wheel, the driven member being 
located between the two raybestos discs, “F.” A 
large spiral coiled spring, bearing against the 
housing cover and the disengaging collar, sup¬ 
ports the toggle disengaging members con¬ 
nected with the driving plate. This housing “D” 
has two slots “C” which carry screws “A” at¬ 
tached to the toggle mechanism, which form an 
adjustment for wear. 

The Clutch Brake. 

All clutches possess a certain inertia when 
they are disengaged, and this 4nertia causes spin¬ 
ning and makes gear shifting somewhat difficult. 
For this purpose a clutch brake is used which 
overcomes the spinning effect. 

Care of the Clutch. 

A clutch should always be engaged slowly and 
carefully to prevent a sudden jar to the entire 
mechanism. Slipping the clutch should be 
avoided, and if slippage is noted it should be 
corrected. More harm can be caused by slip¬ 
ping in one trip than would occur if used with 
discretion one season. Parts requiring lubrica¬ 
tion should be kept well supplied. 


Electric Starters 


T HE gasoline automobile engine is an amaz¬ 
ing example of engineering ingenuity, fur¬ 
nishing power at a less weight than any 
other form of engine, but it is peculiar in that 
it cannot start itself. This is because its cycle 
o*f operations includes only one stroke in which 
power is delivered to those in which it actually 
requires energy. Once it is running, the energy 
for those three waste strokes is supplied by the 
spinning fly-wheel; but to start it this energy 
must be furnished by some outside means. Hence 
the necessity of providing a starting crank, or 
the more popular equivalent, the starting motor. 

The electric starting system is now universally 
used and usually is combined with an electric 
lighting system. Since some source of current 
supply and storage must be used, it is necessary 
to provide a generator and a battery. These 
three component parts make a complete elec¬ 
trical equipment. For the convenient distribu¬ 
tion and control of the current, such units as 
switches, ammeters, connectors, wiring, etc., are 
also included. The motor and generator may 
either be arranged in separate units or combined 
in one unit. Both types are quite popular and 
have peculiar advantages of their own. 

The Generator. 

The generator is incorporated for the purpose 
of producing current. These generators are of 
two types, the permanent and excited or wound 
field types. The voltage of electric systems 
varies considerably; however, the six and twelve- 
volt systems are leading types now being used. 

(157) 


158 


Autocraft 


This generator is always mechanically driven 
from the engine, either by direct drive or through 
a belt or chain, depending on the generator speed 
and the chassis design in general. 

The Storage Battery. 

All current produced by the generator and not 
consumed by the lamps or other electrical units 
passes through the storage battery and held 
in reserve for starting or lighting when the car 
is at a standstill, or for lighting and ignition 
when the car is being run at very low speeds. 

These batteries are of special design to give 
maximum efficiency and working life under the 
severe conditions of motor car operation. The 
mounting of this unit is generally determined by 
the conditions of appearance and accessibility, 
three positions being available—under the body, 
seats, or running-boards. When mounted on the 
running-board it is usually set into a steel battery 
box for mechanical protection and appearance. 

The Starting Motor. 

The motor, which takes the place of the more 
common hand-crank, is operated by electric cur¬ 
rent from the battery, and in revolving it cranks 
the engine, the power being applied by individual 
methods in different systems. 

Controls. * 

Automatic operation of the three units men¬ 
tioned above requires several mechanical and 
electrical controls, which are termed the circuit 
breaker, the governor, and switches. 

The circuit must positively and automatically 
open the circuit between the generator and bat¬ 
tery when the car is standing or running slowly, 
so that the battery cannot discharge current back 
through the generator. This circuit breaker is 
usually Operated by an electro-magnet and may 


Electric Starters 


159 

either be built into the generator or in a separate 
unit. 

The governors are designed to automatically 
prevent an excess output of the generator, and 
they may either operate mechanically or elec¬ 
trically. The mechanical governor is a friction- 
driven mechanism mounted on the generator 
shaft and automatically limits the speed of the 
generator to a fixed number of revolutions per 
minute. The maximum output of the generator 
is in this way held to a certain predetermined 
amount, independent of the speed of the engine 
or car. The purpose being to prevent the pos¬ 
sibility of overcharging the battery 6r overheat¬ 
ing the generator. The electrical governor has 
nothing to do with the speed of the generator, 
but controls its output by means of armature 
reaction and a reversed series field winding. 

The Ammeter. 

Some means must be provided for indicating 
at all times the amount of current being pro¬ 
duced by the generator or discharged from the 
battery. This instrument is usually mounted in 
plain view of the operator on the cowl or dash 
and is called the ammeter. 

Switches. 

The lighting switch is also mounted on the 
cowl or dash within convenient reach of the 
driver. It is made up of a number of units so 
that the head, side and tail lamps may be con¬ 
trolled independently of each other. 

The purpose of the starting switch is to com¬ 
plete the circuit between the starting motor and 
the battery when it is necessary to start the en¬ 
gine. It is generally arranged to be operated with 
' the foot and may either be installed on the foot¬ 
board or near the starting pinion. 


160 


Autocrajt • 


Wiring. 

The wiring for either starting or lighting are 
independent of each other and are easily recog¬ 
nized, as the starting wire is always of single, 
heavy, round conductor cable, while the lighting 
wire is of much smaller twin conductor cable 
or single strand cable. 

There are a variety of systems in use at pres¬ 
ent; however, several will be illustrated to assist 
in describing the general construction. 


Fig. 80 illustrates the Autolite starter and its 
mounting on the Chevrolet cars. A small pinion 



Fig. 80.—Cross Section of Auto-Lite Starter on Chevrolet Six. 


is mounted on the armature shaft of the start¬ 
ing motor, which meshes with an internal gear 
mounted within a housing attached to the start¬ 
ing: motor. This gear is mounted on a shaft 
which carries the governor over-running clutch 
and also a pinion which may be shd into mesh 
with a gear mounted on the fly-wheel. This 
sliding pinion is shifted by means of a fork and 
shaft connected with a foot pedal. The shifting 
shaft is also connected with the starting, shaft 
so that the pinion can be meshed with the fly¬ 
wheel and the circuit completed between the 
starting motor and the battery. 









































Electric Starters 


161 


Rush more Starting and Lighting System. 

The Rushmore Engine Starter and Dynamo 
are distinguished by extreme simplicity of mech¬ 
anism, and action so completely automatic that 
none of the usual manipulations are needed either 
in starting the engine or in regulating the charge 
delivered at the battery. 

The Starter acts directly on the flywheel, the 
usual intermediate gears being omitted. A pinion 



Fig. 81.—Rushmore Starter. 


on the armature slips automatically into mesh with 
the flywheel gear when the button is pressed, turns 
the engine over at a rate of 75 to 300 r. p. m., 
and slips automatically out of mesh again as soon 
as the engine picks up. The operator has nothing 
whatever to do with the performance after the 
button is pressed. 

The illustration shows the starting motor in 
section with the armature out of action. The 
pinion at the right-hand end of the shaft is keyed 
fast, and the whole armature moves bodily end¬ 
wise with its shaft to engage and disengage the 
pinion. The left-hand end of the shaft is hollow 
and carries a compression spring by which the 

















162 


Autocraft 


armature is held out of action in the position 
shown. In this position the armature is out of 
line with the pole pieces of the field magnet. 

When the starting switch is closed the attraction 
of the pole pieces draws the armature strongly to 
the left, thus meshing the pinion and causing the 
armature to turn. 

With the first explosion the armature is relieved 
of its load and the current which it draws from 
the battery drops instantly almost to nothing, so 
that the attraction of the pole pieces is not suffi¬ 
cient to hold the armature in its working position. 
The spring, therefore, instantly pushes the arma¬ 
ture to the right, thus slipping the pinion out of 
mesh before one can notice any increase in speed. 

To insure the pinion meshing properly when the 
switch is closed the switch has^ two active contacts. 
The first contact practically short-circuits the 
armature and puts the field coil in series with a 
resistance. The effect is that the first contact 
gives the armature only enough turning motion 
to make sure that the pinion goes into mesh. The 
second contact cuts out the resistance and puts 
the armature in circuit so that it starts to turn the 
engine. 

The Rushmore Dynamo is distinguished by hav¬ 
ing no mechanical current regulator. The output 
is governed by utilizing a peculiar property of iron 
wire, namely, that of increasing greatly in resist¬ 
ance at a critical temperature a little below red 
heat. The manner in which this property is util¬ 
ized is simple and highly ingenious. The dynamo 
field magnet is wound with the usual shunt coil, 
and in addition with a “bucking coil” which is in 
series with the external circuit, so that the current 
delivered at the battery and lamps goes through 
the bucking coil. The effect of the bucking coil 
is to reduce the excitation of the field magnet. 
This reduction in strength is, however, desired 


Electric Starters 


163 


only at low speeds, and here is where the iron 
“ballast coil,” as it is called, comes in. This 
ballast coil, consisting of a simple strand of stove¬ 
pipe wire 10 inches long, is arranged as a shunt 
across the terminals of the bucking coil, so that 
the current delivered, instead %f passing wholly 



Fig. 82.—No B Dynamo with Cover C Removed of Busher. 


through the bucking coil, divides between the 
bucking coil and the iron ballast coil on its way 
to the battery and lamps. When the ballast coil 
is cold it practically short circuits the bucking coil 
so that the latter has very little effect. As the 
speed of the dynamo increases its output increases 
also very rapidly, up to the point where the ballast 
coil becomes hot. When the delivery exceeds 
about 12 amperes the resistance of the ballast coil 
increases so much that a considerable portion of 
the current is forced to find a path through the 
bucking coil, thereby reducing the excitation of 
the field magnets. 





164 Autocrajt 

A switch connected to the headlight switch cuts 
the ballast coil out of circuit, so that all the cur¬ 
rent from the dynamo has to go through the buck¬ 
ing coil; this reduces the output to about three 
amperes average when the headlights are out of 
use. This small current suffices for the demands 
of the small lamps, horn, ignition system, etc. 
Owing to the normal output being so large, the 
battery is not drawn upon at all when the lamps 
are lighted, unless the speed drops below about 
15 miles per hour. Consequently the usual day¬ 
light recharging is unnecessary, and danger of the 
battery being unexpectedly exhausted by excessive 
night driving is eliminated. 

CUT-OUT. 

An automatic cut-out operated electrically, per¬ 
forms the function of connecting and disconnect¬ 
ing the generator and battery when the proper 
speed of the generator is reached. This connec¬ 
tion is established when the engine has reached 
the speed that would propel a car on high gear at 
about eight miles per hour. It is then that the 
generator begins charging the battery, the rate of 
charge increasing until the car reaches approxi¬ 
mately fifteen miles per hour, at which point the 
governor on the generator becomes operative and 
maintains constant armature speed. This means 
that the charging rate is constant regardless of 
the variations of engine speed above that required 
to propel the car fifteen miles per hour, and the 
commutator winding and brushes are not subject 
to excessive friction or speed. When the speed is 
reduced below fifteen miles per hour, the governor 
becomes inoperative as the machine slows down 
and as the car reaches the speed of approximately 
six miles per hour, the voltage of the generator is 
reduced to a point less than that of the battery, 
which permits a slight reversal of the flow of the 
current through the cut-out heavy winding. 


Electric Starters 


165 



Fig. 83.—Evolution of the Electric Motor. 


Inasmuch as there is still a low voltage current 
flowing from the generator through the fine wind¬ 
ing on the cut-out coil, the effect of the reversal 
of the battery current is to cause a partial neutrali¬ 
zation, thus reducing the strength of the magneto 
field which holds, by means of a movable arma¬ 
ture, the contact points on the cut-out together. 
When this neutral point is reached a spring forces 
the two points apart, thus disconnecting the bat¬ 
tery from the generator and preventing any waste 
of current. As this action is instantaneous, there 
is positively no way in which the battery current 
can run back through the generator. This is a 
very important feature and should not be under¬ 
estimated. As a further matter of protection, 
the cut-out armature is housed, so that it cannot 
be cut in accidentally. 



Fig. 84.—Starting Motor Disassembled. 

































The Universal Joint 


U NIVERSAL joints serve the purpose of 
connecting shafts or control rods whose 
axis lie in the same plane but make an 
angle with each other. This condition applies 
to the drive shaft; however, a still greater diffi¬ 
culty exists, as the angle continually varies in 
practice. 

In a chain-driven vehicle the motor and trans¬ 
mission usually remain in alignment when the 
vehicle is standing still; however, road vibrations 
and irregular loading cause frame deflexions 
which tend to destroy the alignment. In this case 
it is only necessary to have a universal which 
operates at a small angle. Now, in a shaft-driven 
vehicle the road wheels are continually bounc¬ 
ing over the rough surface of the road, while 
the movement of the frame at the front which 
supports the power plant is limited by the chassis 
springs. Thus, at one moment the axle is directly 
in line with the power plant, and the next moment 
it may be several inches above or below the motor 
center. The universal joint practically makes a 
flexible member to compensate for all these ir¬ 
regularities. 

Engineers seem to differ as to the number of 
universal joints that are necessary in a shaft- 
driven vehicle. In some cases but one is used, 
while in others two are used. When the pro¬ 
peller shaft is enclosed in a torque tube but one 
joint is used; however, when an open drive is 
employed it must be provided with two universal 
joints. 

In any type of shaft drive, regardless of pro¬ 
peller shaft or torque tube construction, one 

( 166 ) 


167 


Universal Joint 

universal must have what is termed a slip joint. 
In a chain-driven vehicle this slip movement is 
usually provided to compensate for the clutch 
movement in clutch disengaging and for varia¬ 
tions in shaft lengths. It is also of considerable 
advantage in assembling the chassis. 

This slip joint is necessary in shaft-driven 
vehicles, since some provision must be made to 
compensate for variations in the distance between 
the transmission and the rear axle housing due 
to the play of the springs. 

Drive shafts are generally made of solid sec¬ 
tion; however with the increasing tendency to¬ 
ward the ufe of unit power plants arises the 
question of using hollow shafts, as with this 
construction the shaft length is increased con¬ 
siderably, and in order to overcome the whipping 
effect, its weight must be reduced as well as the 
pressure on the bearings. 

The present tendency in motor truck design 
is toward shaft drive and a long wheelbase, 
which calls for a shaft of considerable length, 
so that it is necessary to reduce the whipping 
effect to a minimum. However, this is impos¬ 
sible even with very tight wall tubing of large 
diameter. This has resulted in the introduction 
of three universals and two shafts; one being 
attached to the transmission supporting one end 
of a shaft, while the other end of the latter is 
supported by a bearing from a frame cross¬ 
member. From this point the drive is through 
two universal joints and a shaft in the usual 
manner. 

Square Block Type. 

The simplest type of universal joint consists 
of square blocks secured to or forged integral 
with the ends of the shafts to be connected, fit¬ 
ting in a square hole in a sleeve secured to the 
driving and driven units. The four faces ot 


168 


Autocrajt 


these blocks are curved in the direction of the 
axis of the shaft. This type of joint, owing to 
its limited angular movement is only used on 
chain-driven vehicles between the clutch and 
transmission. This construction is shown in Fig. 
1, in which the square blocks are forged integral 
with the drive shaft. One sleeve is bolted to the 
clutch which forms the driving unit, while the 
other is bolted to the transmission or driven 
unit. This type also constitutes a slip joint, and 
springs are used to hold the shaft central. 
Leather boots are provided to enclose the sur¬ 
faces and act as a retainer for grease. It can 
readily be understood that owing to the curvature 
of the faces of the blocks, one of the units can 



be moved angularly with relation to the other in 
two planes at right angles to each other. This 
type of joint may also be used on pleasure ve¬ 
hicles where the transmission is mounted amid¬ 
ships. With the unit power plant perfect align¬ 
ment is always maintained and universals are 
not necessary between the motor and transmis¬ 
sion. 

The Frictionless Universal Joint. 

The frictionless universal (Fig. 86) is gaining 
favor for use between motor and transmission 
when these are mounted separately. This con¬ 
sists of two forks placed at right angles to each 
other, which are connected by a fabric disc. This 
type of joint is limited to operation at angles. 











Universal Joint 


169 



Fig. 86.—Universal Joint. 


The modern universal joints used for connect¬ 
ing shafts, where their angle varies greatly, are 
sometimes called Hooke or Cordan joints. Pres¬ 
ent types are modifications of these and at present 
these are made by manufacturers who devote 
their entire production to this article. In a work 
of this kind it is impossible to illustrate every 
make; however, the principal ones are illustrated. 

The Spicer Universal. 

The Spicer is illustrated in Fig. 87, which is an 


TU.AX PACKING 
OUTER CASING 

caging adjusting nut 
- rccr washer 



COTTER PIN 
CREASE HOLE PLUG 


Fig. 87.—Spicer Universal Joint, showing Slip Joint. 














































170 


Autocraft 


excellent example of a modified Cordan joint. 
This comprises a central ring with pins forged 
integral, having their axles in the same plane. 
One forked end is integral with a hub which bolts 
to the hub of either driving or driven shaft end, 
while the fork may either have a short hub for 
permanent attachment or a long one for slip 
movement, the slip end being shown. The bear¬ 
ing ends of the forks have an opening large 
enough to permit inserting the pins, while they 
are also bored out large enough to take bushings 
which hold the ring and its pins in position. 
These bushings and forks have a circular groove 
cut into them, so that a soft wire can be inserted 
to hold the bushings in position. The entire 
joint is enclosed in a dust-proof pressed steel 
housing which also acts as a retainer for lubri¬ 
cant. 


Fig. 88.—Hartford Universal Joint. 



The Hartford Universal. 

This, joint (Fig. 88) differs somewhat from 
the Spicer in detail. Instead of the central ring 
being provided with four pins it is arranged 
with four bosses equally spaced, which carry 
hardened steel bushings. Two of these bosses 
fit into a fork which is formed integral with a 
hub, while the other two fit into the forked end 
of the shaft at one end, while on the other they 
fit over flat surfaces on the slip joint hub. These 
rings are retained by one long and two short 
pins as shown. Washers and cotter pins hold 
the long ones in position, and the shorter ones 


















Universal Joint 


171 


resemble clevis pins and are also retained by 
cotter pins. The joint proper is enclosed and 
the pins have slots so that the lubricant can reach 
the bearings. 

The Blood Universal. 

This is also of the pin type, but differs in the 
method of inserting the pins. The center ring is 
replaced by a steel cube which enters the fork 
ends. The cube together with the pins forms a 
cross. ■ One pin has an enlarged surface which 
fits into the cube, while the other is of one diam¬ 
eter and passes through the former and the cube. 
A small pin is inserted to lock both of these in 



position. Each fork has hardened steel bushings 
which extend far enough to receive a grease cup, 
as shown in Fig. 89. 

The Block and Trunnion Type. 

Fig. 90 depicts this type of joint, which con¬ 
sists of a cup-shaped steel forging secured to one 
of the shafts, with two diametrically opposite 
longitudinal slots milled into its shell. The other 
shaft is provided with a ball-shaped end, fitting 
the interior of the shell and provided with pins 
or studs extending into the slots. Hardened steel 
trunnion blocks are interposed between the pins 
and the walls of the slots to distribute the bear¬ 
ing pressure. This type of joint, it will be noted, 
serves also as a slip joint. It can readily be en¬ 
closed by leather boots and represents a type 











































172 


Autocraft 



which has been extensively used. An entirely 
different type is shown in Fig. 91. On this the 
usual center ring is replaced by a spiral-shaped 
center piece having two internal and two external 
radial slots. The permanent yoke has two radial 
projecting surfaces, which fit into the external 
slots, while the pivoting member has two pro¬ 
jecting surfaces which fit into the internal slots. 
The internal and external slots in the center 
piece alternate so that a spiral movement is ob¬ 
tained in any direction. A steel housing fits 
snugly over the external member and has a spiral 
bearing, while a cover is attached to it which 
retains the entire mechanism. 


For some time these universals were not en¬ 
closed, and it was found difficult to lubricate them 
effectively. Centrifugal force would cause them 
to throw off oil and grit would work into the 
bearings. However, this difficulty has entirely 
been overcome by enclosing the universals in a 
dust-proof housing. 












































The Motor Cooling System 

I T is the general impression that the office of 
the cooling system is to abstract the heat from 
the gases within the cylinders, this heat having 
been generated by the explosion. This impression 
is an erroneous one, for, as a matter of fact, the 
duty of the cooling medium is to keep the cylinder 
walls cool, the heat of the gases being converted 
into useful energy. These cylinder walls must 
be kept cool for two reasons. One is to permit 
of proper lubrication, without which the piston 
could not travel up and down in the cylinder. 
Lubricating oils have a definite flash point, and 
when this temperature is reached they will burn 
and leave a carbon residue. Thus it can readily 
be understood that the cylinder walls must be kept 
cool to prevent the carbonizing of the lubricating 
oil. 

The second reason is to prevent pre-ignition. 
If the metal be permitted to heat up to a red 
heat, for instance, the fuel will ignite during the 
compression stroke, previous to the completion 
of same, and thus cause the engine to reverse. 

There are two general types of cooling systems, 
the direct or air system, and the indirect or water 
system. The air system being termed a direct 
system, as there is no intermediate transfer of heat 
from the cylinder walls to the radiating surfaces, 
by means of a cooling liquid. Air cooling is gen¬ 
erally effected by cooling ribs, which are cast 
integral with cylinder wajls and some mechanical 
method of inducing air circulation. 

The indirect cooling system involves the circu¬ 
lation of a liquid, such as water, the function of 
which is to absorb heat from the cylinder walls 

(173) 


174 


Autocrajt 


and deliver same to a current of air which ia 
passed over the surfaces of a radiator within 
which the water in its heated state is circulated, 
by means of a circulating pump, except in the 
cases involving the thermo syphon system of cir¬ 
culation. All water-cooled motors, so-called, are 
of the indirect cooled type. 

The indirect system may be depicted as fol¬ 
lows: Water is passed from the lower tank of 
the radiator to the pump mounted on the engine, 
which forces the water through a distributing 
manifold to the various cylinders of the engine. 
This water is usually entered at the bottom of 
the water jackets, and as it becomes heated 
it loses its specific gravity, rises, and flows out 
through the upper manifold to the top of the 
radiator, where it is distributed to the various 
tubes, through which it flows to the lower tank 
and is again circulated. These radiator tubes are 
separated by air spaces through which air passes, 
carrying off the heat units in the water. 

The thermo syphon system is generally referred 
to as the natural circulating system. In this sys¬ 
tem the pump is eliminated and the circulating 
is induced by the heat of the motor. The water 
under the influence of heat sets up a circulation, 
and it can readily be understood that the heat re¬ 
places the pump as the moving force acting on the 
water. 

In order that the cooling may be effective in¬ 
dependent of the car speed, a fan must be used. 
To cool an engine as used in the modern type of 
motor car, under ideal conditions and most 
efficiently, would require a tremendously large 
radiator, if the car stood still, or the air was 
allowed to flow through it naturally. So to reduce 
the size to something that can be used, the relative 
efficiency is increased. This is done by inducing 


Motor Cooling System 


175 


an artificial flow of air. This is brought about 
in two ways. One is that the radiator does not 
stand still, but is moved with the car, indicating an 
air circulating through it. This, however, would 
not be effective with the car standing still and 
the engine running, so a second artificial circulat¬ 
ing means is provided in the fan. This fan is 



driven from the engine and so rotates when the 
engine rotates. If the engine runs slowly and has 
little heat to dispose, the fan runs slowly. When 
the former turns over at the maximum rate of 
speed, the fan, too, is making the highest possible 
number of revolutions. The fan is most generally 
placed at the front end of the engine and directly 
in the rear of the radiator, drawing air through 
the radiator only, while lately there has been a 
tendency to combine the fan with the fly-wheel, 
drawing air through the radiator and thence across 
the whole engine, thus effecting secondary cooling. 

Many different constructions of radiators are 






















































176 


Autocraft 



in evidence upon the later models of motor 
cars, among which may be found the honeycomb, 
sometimes called the cellular, flat vertical tube 
and the built up round and flat tube types. 

The honeycomb type con¬ 
sists of a series of six-sided 
or hexagonal tubes fastened 
into a header in such a way as 
to allow of space between the 
tubes for the passage of water. 
This construction is quite ex¬ 
pensive and was generally 

Fig. 93.— Honeycomb f ° Utld 011 the hi S h P«Ced Cars. 

Type. This was later replaced by 

what is known as the cellular type, generally be¬ 
ing termed honey¬ 
comb type. The con¬ 
struction is similar to 
that depicted above, 
excepting that square 
tubes are used instead 
of hexagonal. Flat 
vertical tubes, tubes 
with square corruga¬ 
tions and swaged or 
soldered edges to 
form water spaces 
are also used. 


The flat vertical tube 
type consists of a 
series of rectangular 
shaped tubes fastened 
into a header, with 
fins attached to the 
tubes for heat radia¬ 


Fig. 94.—Mercedes Type. 


tion and to strengthen vertical tubes. Vaiious 
types of fin construction are used, and sometimes 
these are of the continuous type, the result of this 














Motor Cooling System 


177 


construction being a pleasing appearance similar 
to the cellular type. This latter type is more pop¬ 
ular on the light popular-priced motor cars owing 
to its lower first cost. 

In the majority of motor cars the radiator is 
located at the front end of the car, and so set 
that the air currents pass almost unobstructed 
through the passage ways. 



This radiator is quite a frail unit and when the 
car is built in a unit with the outer shell it is quite 
difficult to obtain a stream-line effect for entire 
car. In order to overcome this, a shell is generally 
drawn to proper shape and the radiator arranged 
so that this can be bolted in the shell after it has 
been enameled. The Reo radiator shown here¬ 
with is of this construction. 

There are two general types of pumps in use 
at the present writing, the gear type and the centri¬ 
fugal type. 
































































178 


Autocrajt 



Fig. 97.—Forced Circulating System. 














































































Motor Cooling System 


179 


The essentials of the gear type of pump consist 
of a pair of gears, a pair of shafts for them to 
rotate on, and a case to house the gears, which 
acts as bearings for the shafts and to convey 
the water to and from the gears in the proper 
manner. 

Water enters at the side of the meshing teeth 
and is carried around between the teeth and the 
housing to the outlet on the opposite side. The 



CENTHPUGAL PUMP. 


Fig. 98.—Motor Cooling. 

gear pump is simple in construction and main¬ 
tenance. 

As previously mentioned, eight and twelve- 
cylinder engines are generally provided with dou¬ 
ble water pumps arranged in a single unit. An 
example of this type is the Packard twin six 
pump, which consists of a double rotating num¬ 
ber and double outlets which are arranged op¬ 
posite each other. A single inlet is provided 
which communicates with the center of the rotat¬ 
ing member and permits the water to be forced 
tending from the turning gear housing and are 
out through both outlets, each of which are con¬ 
nected with a cylinder bloc. 

Both the gear and centrifugal types of pumps 
possess an advantage over all other types, in 
that they provide a continuous stream of water. 


























180 


Autocraft 



Fig. 99.—Packard Twin Six Pump. 




































Motor Cooling System 181 

Between these two types there is very little or no 
choice; they both do the work under substantially 
the same conditions, unless it is that the gear 
pump is more likely to become noisy. 



The centrifugal type of pump is perhaps the 
easiest of all to understand. It consists of a ro¬ 
tating member, which may either be formed in¬ 
tegral with or keyed to the driving shaft, and a 
case and cover which house the rotating member. 
In operation it is rotated at high speed and the 
water entering at the center flows out on the 
arms and at the extremities is thrown off by cen¬ 
trifugal force. This throwing off action is re¬ 
stricted by the case, so that the effect is to throw 
the water into the outlet pipe. 

The pumps are generally driven by shafts ex- 
provided with flexible or universal couplings. The 
coupling serving to keep the pump free from 
strains due to misalignment, and it is also in some 
cases so designed that when the pump freezes up 
the coupling will break before any damage is done 
to the pump. 























































182 


Autocrajt 


Lately there has been a tendency to increase 
the size of the inlet and outlet pipes of the cooling 
system, providing" as few bends as possible, in 
order to obtain a free passage for the water. 
Besides having these manifolds of adequate area, 
it is also necessary to arrange these manifolds 
so that one cylinder will not rob the other of its 
share of the cooling fluid. 


Electric Wiring Plan and Coil 
Adjustment 

Things to Know That Save Trouble. 

S HORT CIRCUITS. Any battery will be 
rapidly exhausted if it is allowed to stand on 
short circuit for any length of time. For this 
reason care should be taken not to place metal 
bars, tools, etc., on the battery where they might 
short circuit it. 

When starting a car equipped with a dual 
system of ignition, the car should be cranked 
immediately after the switch is turned to the 
battery side and the magneto switched in at once. 
This is necessary, because in the majority of such 
systems the battery is short circuited all the time 
that the switch is on the battery side. 

It is also well to thoroughly examine the switch 
on any system and to be sure it is free from any 
short circuits either when the switch is in the off 
position or on the magneto side. In many cases 
the battery has been found to be short circuited 
when the switch was on the magneto side or even 
in the off position. 

Wiring. For primary wiring use about No. 
14 gauge wire with approved insulation. 

For secondarv wiring special heavily insulated 
high tension wire should be used at all times. 

Apparatus should be placed so that the length 
of the secondary leads shall be reduced to the 
minimum. These leads should not be placed too 
close to each other if they are more than 24 inches 
long. 

High tension wires should never be placed so 
that they are liable to become soaked with oil or 
water. 


(183) 


184 


Autocrajt 


Wires should never be left with loose ends ex¬ 
posed. They will cause trouble. 

A loose contact will always cause trouble. The 
wires should be scraped until they are clean and 
bright after the insulation has been removed and 
all the joints should be made secure and taped. 

Care should be taken that the ground wire 
makes good contact with the engine frame (not 
the body frame) in such a position that it is not 
liable to be broken. 

All connections should be inspected regularly 
for loose or corroded joints. 

Spark Plugs. Those that give satisfactory 
service on battery systems are often destroyed 
within a short time when used on magneto. Spark 
gaps about 3/64 inch, or the thickness of a dime, 
will give good results with batteries. 

In replacing spark plugs in hot cylinders, do 
not screw them in too tightly. They will be hard 
to remove. 

General. Do not operate an ignition system 
with the secondary wires removed, unless a spark 
gap is provided through which the secondary may 
discharge. 

Do not take it for granted that the ignition is 
at fault every time the engine stops or misses. 

When using individual dry cells in steel battery 
box some form of lining should be provided. 
Ordinary floor matting makes an excellent lining. 

When replacing a storage battery with dry cells 
the interior of the battery box should be thor¬ 
oughly scrubbed to remove all acid, otherwise the 
zinc of the battery will be attacked and quickly 
destroyed. Cases have been known where a num¬ 
ber of drv cells have been destroyed within a few 
days by the acid left in the battery box from a 
storage battery which was formerly used. 

When using individual dry cells care should be 


Electric Wiring Plan 


185 


exercised in washing the car, so that the batteries 
and the interior of the battery box are not wet. 
This is apt to cause leakage of current, which will 
soon destroy the batteries. 

Causes of Ignition Troubles. 

In 99 cases out of 100 the motorist blames the 
batteries whenever anything goes wrong with his 
ignition. Experience has proved that the reverse 
of this is the actual condition. 

As a guide to those who may be having ignition 
trouble we will list a few conditions and show 
some possible causes for the trouble, independent 
of the battery. 

(a) Whenever the engine fires irregularly, the 
cause may he due to: 

(1) Broken down insulation on wires. 

(2) Carburetor not properly adjusted, caus¬ 
ing poor mix. 

(3) Cracked spark plug. 

(4) A defective connection in some part of 
the circuit. 

(5) Gasoline feed partly choked. 

(6) Moisture on spark plugs or water in 
carburetor. 

(7) Poor contact in timer. 

(8) Spark coil not properly adjusted. 

(9) Terminals on coil may be loose or dam¬ 
aged. 

( b ) When the engine fires regularly, hut is 
weak, the cause may he due to: 

(1) Compensating valve on carburetor not 
working. 

(2) Improper gas mixture. 

(3) Insufficient lubrication. 


18 6 


«r 


Autocraft 


(4) Platinum contacts on coil may need clean¬ 
ing. 

(5) Poor compression caused by loose plugs 
or valves. 

(6) Reduced lift on exhaust valve. 

(7) Muffler outlets may be stopped with mud 
or charred oil. 

(8) Vibrator on coil may need adjusting. 

(9) Weak spring on inlet valve. 

( c ) When the engine refuses to start, the 
cause may he due to: 


(1) 

Broken or jammed gears. 


(?) 

Dry cylinders. 


(3) 

Battery plug not in position. 


(4) 

Fouled or cracked spark plug. 


(5) 

Gasoline shut off. 


(6) 

Improper gas mixture. 


(7) 

Improper Ignition. 


(8) 

Inlet valve stuck. 


0) 

Open battery switch. 


(10) 

Poor compression. 


(11) 

Water in cylinder caused by leak 

from 

water jacket. 


(12) 

Water in gasoline. 


(d) 

When there is a gradual slozving up of 

the engine, accompanied by misfiring, the 
may he due to: 

cause 

(i) 

Carburetor may be choked with dirt at jet. 

(2) 

Gasoline tank empty or air-bound. 


(3) 

Gasoline valve partly closed. 


(4) 

Fouled spark plugs, due to over or 

poor 


lubrication. 


Electric Wiring Plan 


187 


These are not all of the things that may cause 
your trouble, but serve to show you that there are 
many angles to the ignition question independent 
of the battery of whatever make or grade. 

To sum up in a few words, here are a few 
things that may be the direct cause of poor igni¬ 
tion, and each has no connection with battery 
qualities. (1) Poor or loose connections in the 
wiring; (2) Poor battery connections ; (3) Broken 
down insulation ; (4) Fouled or leaky spark plugs ; 
(5) Broken wires under the insulation somewhere 
in the circuit; (6) Defective switch; (7) Defec¬ 
tive units in good types of coils; (8) Poor coils; 
(9) Impeded flow of gasoline; (10) Improper ad¬ 
justment of carburetor; (11) Poor vibrator ad¬ 
justment; (12) Leaky valves—and many other 
causes. 


Valve Grinding 

I F the average car owner only realized the im¬ 
portance of keeping the valves properly seated! 
Too much emphasis cannot be placed on the 
necessity of examining them carefully at regular 
intervals, even though the compression is appar¬ 
ently normal and uniform in each cylinder. The 
exhaust valves are especially susceptible to corro¬ 
sion on account of the intense heat of the escaping 
gases. The seats soon becqfne pitted, the carbon 
dust and vapor is caught and confined in every 
little crevice, and in an incredibly short space of 
time the valves, if neglected, will be covered with 
a deposit of carbon which will affect the running 
of the motor to a marked degree. The only rem¬ 
edy is to grind them. 

Remember, you must by all means prevent even 
a minute particle of this grinding abrasive from 



188 


Valve Grinding 


finding its way into the combustion chambers. 
Pack a good, generous quantity of waste or rags 
well soaked in gasoline around the valve seat and 
take due precaution to leave the inside of the 
cylinder casting perfectly clean. 

Apply a moderate coating of the compound to 
the bevel face of the valve and return it to its 
seat. Next rotate valve forward and back until 
the entire bearing surfaces are polished bright and 
smooth the full width of the face. If the guide is 
worn or the stem bent great care must be exer¬ 
cised or the valve will not be “true”—i. e., the 
bevel face will not be flat, but a trifle convex. 
The valve should never be turned the whole way 
round. Oscillate it back and forth a quarter turn 
at most under light pressure, lifting it up fre¬ 
quently and turning it half way round before seat¬ 
ing it again. This method distributes the friction 
evenly and eliminates the possibility of the emery 
scoring the bearings. If no valve grinding tool 
is available, the use of a carpenter’s bit stock is 
advised, as a much smoother movement is thus 
obtained than by using a screwdriver. 

After working up a good clean seat, entirely free 
from spots or pits, wash the valve, valve seat and 
guide thoroughly in gasoline. If the stem is rough 
or gummy, smooth it up with emery cloth, but 
clean it afterwards and oil it before replacing. 










































































































